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Susitna‐Watana Hydroelectric Project Document
ARLIS Uniform Cover Page
Title:
Groundwater study, Study plan Section 7.5, 2014-2015 Study
Implementation Report SuWa 289
Author(s) – Personal:
Author(s) – Corporate:
R2 Resource Consultants, Inc. ; Geo-Watershed Scientific ; Pacific Groundwater Group.
AEA‐identified category, if specified:
November 2015; Study Completion and 2014/2015 Implementation Reports
AEA‐identified series, if specified:
Series (ARLIS‐assigned report number):
Susitna-Watana Hydroelectric Project document number 289
Existing numbers on document:
Published by:
[Anchorage : Alaska Energy Authority, 2015]
Date published:
Main report and Appendices A and C:
November 2015
Appendices B and D:
October 2015
Published for:
Alaska Energy Authority
Date or date range of report:
Volume and/or Part numbers:
Study plan Section 7.5
Final or Draft status, as indicated:
Document type: Pagination:
310 pages total in 5 volumes
Related work(s): Pages added/changed by ARLIS:
Notes:
Contents:
2014-2015 Study Implementation Report
Appendix A. Preliminary water table contour maps for Focus Areas FA-104 (Whiskers Slough),
FA-115 (Slough 6A), FA-128 (Slough 8A), and FA-138 (Gold Creek) / prepared by Pacific
Groundwater Group
Appendix B. Preliminary MODFLOW three dimensional groundwater model for FA-128 (Slough
8A) / prepared by Pacific Groundwater Group
Appendix C. Summary review of Susitna River hydrogeologic studies conducted in the 1980s with
relevance to proposed Susitna-Watana Dam Project and other non-Project related studies /
prepared by Pacific Groundwater Group
Appendix D. December 5, 2014 Technical Team Meeting notes and presentation / prepared by
Geo-Watershed Scientific.
The main report and each appendix of Section 7.5 appear in separate electronic files.
All reports in the Susitna‐Watana Hydroelectric Project Document series include an ARLIS‐
produced cover page and an ARLIS‐assigned number for uniformity and citability. All reports
are posted online at http://www.arlis.org/resources/susitna‐watana/
Susitna-Watana Hydroelectric Project
(FERC No. 14241)
Groundwater Study
Study Plan Section 7.5
2014-2015 Study Implementation Report
Prepared for
Alaska Energy Authority
Prepared by
R2 Resource Consultants, Inc.
Geo-Watershed Scientific
Pacific Groundwater Group
November 2015
2014-2015 STUDY IMPLEMENTATION REPORT GROUNDWATER STUDY (STUDY 7.5)
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FERC Project No. 14241 Page i November 2015
TABLE OF CONTENTS
1. Introduction ............................................................................................................................ 1
2. Study Objectives .................................................................................................................... 2
3. Study Area .............................................................................................................................. 3
4. Methods .................................................................................................................................. 3
4.1. Existing Data Synthesis ................................................................................................. 4
4.1.1. Variances ............................................................................................................ 4
4.2. Geohydrologic Process-Domains ................................................................................... 4
4.2.1. Variances ............................................................................................................ 5
4.3. Watana Dam/Reservoir .................................................................................................. 5
4.3.1. Variances ............................................................................................................ 5
4.4. Upwelling / Springs Broad-Scale Mapping ................................................................... 5
4.4.1. Variances ............................................................................................................ 5
4.5. Riparian Vegetation Dependency on Groundwater / Surface-Water Interactions ......... 5
4.5.1. Preparation and Submittal of Technical Memorandum – GW/SW Relationships
to Support Riparian Vegetation Modeling ......................................................... 6
4.5.2. Groundwater Technical Team Meeting ............................................................. 6
4.5.3. Preliminary Three-dimensional MODFLOW Model for FA-128 (Slough 8A). 6
4.5.4. Water Table Maps .............................................................................................. 7
4.5.5. Continuation of Data Collection and QC3 Data Review ................................... 8
4.5.6. Variances ............................................................................................................ 8
4.6. Aquatic Habitat Groundwater / Surface-Water Interactions .......................................... 9
4.6.1. Preparation and Submittal of Technical Memorandum – GW/SW Relationships
in Lateral Aquatic Habitats ................................................................................ 9
4.6.2. Groundwater Technical Team Meeting ............................................................. 9
4.6.3. Preliminary Three-dimensional MODFLOW Model for FA-128 ................... 10
4.6.4. Water Table Maps ............................................................................................ 10
4.6.5. Continuation of Data Collection and QC3 Data Review ................................. 10
4.6.6. Variances .......................................................................................................... 11
4.7. Water Quality in Selected Habitats .............................................................................. 11
4.7.1. Variances .......................................................................................................... 12
4.8. Winter Groundwater / Surface-Water Interactions ...................................................... 12
4.8.1. Variances .......................................................................................................... 13
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4.9. Shallow Groundwater Users ........................................................................................ 13
4.9.1. Variances .......................................................................................................... 13
5. Results ................................................................................................................................... 13
5.1. Existing Data Synthesis ............................................................................................... 14
5.2. Geohydrologic Process-Domains ................................................................................. 15
5.3. Watana Dam/Reservoir ................................................................................................ 15
5.4. Upwelling / Springs Broad-Scale Mapping ................................................................. 15
5.5. Riparian Vegetation Dependency on Groundwater / Surface Water Interactions ....... 15
5.5.1. Preparation and Submittal of Technical Memorandum – GW/SW Relationships
to Support Riparian Vegetation Modeling ....................................................... 15
5.5.2. Groundwater Technical Team Meeting ........................................................... 16
5.5.3. Preliminary Three-dimensional MODFLOW Model for FA-128 ................... 16
5.5.4. Water Table Mapping ...................................................................................... 18
5.5.5. Continuation of Data Collection and QC3 Data Review ................................. 19
5.6. Aquatic Habitat Groundwater / Surface-Water Interactions ........................................ 19
5.6.1. Preparation and Submittal of Technical Memorandum – GW/SW Relationships
in Lateral Aquatic Habitats .............................................................................. 19
5.6.2. Groundwater Technical Team Meeting ........................................................... 20
5.6.3. Preliminary Three-dimensional MODFLOW Model for FA-128 (Slough 8A)
20
5.6.4. Water Table Mapping ...................................................................................... 21
5.6.5. Continuation of Data Collection and QC3 Data Review ................................. 21
5.7. Water Quality in Selected Habitats .............................................................................. 21
5.8. Winter Groundwater / Surface-Water Interactions ...................................................... 21
5.9. Shallow Groundwater Users ........................................................................................ 22
6. Discussion ............................................................................................................................. 22
6.1. Existing Data Synthesis ............................................................................................... 22
6.2. Geohydrologic Process-Domains ................................................................................. 22
6.3. Watana Dam/Reservoir ................................................................................................ 22
6.4. Upwelling / Springs Broad-Scale Mapping ................................................................. 22
6.5. Riparian Vegetation Dependency on Groundwater / Surface-Water Interactions ....... 23
6.6. Aquatic Habitat Groundwater / Surface-Water Interactions ........................................ 23
6.7. Water Quality in Selected Habitats .............................................................................. 23
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6.8. Winter Groundwater / Surface-Water Interactions ...................................................... 24
6.9. Shallow Groundwater Users ........................................................................................ 24
7. Conclusion ............................................................................................................................ 24
7.1. Existing Data Synthesis ............................................................................................... 24
7.2. Geohydrologic Process-Domains ................................................................................. 24
7.3. Watana Dam/Reservoir ................................................................................................ 25
7.4. Upwelling/Springs Broad-Scale Mapping ................................................................... 25
7.5. Riparian Vegetation Dependency on Groundwater / Surface-Water Interactions ....... 25
7.6. Aquatic Habitat Groundwater / Surface-Water Interactions ........................................ 25
7.7. Water Quality in Selected Habitats .............................................................................. 25
7.8. Winter Groundwater / Surface-Water Interactions ...................................................... 26
7.9. Shallow Groundwater Users ........................................................................................ 26
8. Literature Cited ................................................................................................................... 27
9. Tables .................................................................................................................................... 30
10. Figures .................................................................................................................................. 44
LIST OF TABLES
Table 4.5-1. Focus Areas and respective target dates for development of Water-Level Contour
Maps for the Susitna River. ................................................................................................... 31
Table 4.5-2. Groundwater Study data collection stations in the Lower River, FA-104 (Whiskers
Creek), PRM 112, FA-113 (Oxbow 1), FA-115 (Slough 6A), FA-128 (Slough 8A), FA-138
(Gold Creek), FA-141 (Indian River), FA-144 (Slough 21), and the ESS Stations. (Updated
ISR Study 7.5 Tables 4.5-1 to 4.5-4.) .................................................................................... 32
Table 4.5-3. Summary of the QC3 data files used in support of this SIR and its appendices that
have been delivered to GINA and are publically available. .................................................. 37
Table 5.1-1. Summary of hydrogeologic parameters identified from the 1980s groundwater
studies and other relevant materials for the Susitna River watershed, Alaska. (Source: SIR
Study 7.5, Appendix C, Table 1.) .......................................................................................... 38
Table 5.5-1. Groundwater and Surface Water Field Stations and MODFLOW Calibration Targets.
(Source: SIR Study 7.5, Appendix B, Table 4-1.) ................................................................. 40
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Table 5.5-2. Model Calibration Results - shaded simulations = best fit model run. (Source: SIR
Study 7.5, Appendix B, Table 5-1.) ....................................................................................... 41
Table 5.6-1. 2014 collected discharge measurements in Focus Areas. (Source: SIR Study 6.6,
Table 5.1-14.) ......................................................................................................................... 42
LIST OF FIGURES
Figure 3-1. Susitna Watershed basin boundaries, showing the Project designation of upper, Middle
and Lower river segments (Source: ISR Study 7.5, Figure 3-1). .......................................... 45
Figure 3-2. Susitna Watershed Middle River Segment, with geomorphic reaches and Focus Areas
indicated (Source: ISR Study 7.5, Figure 3-12.) ................................................................... 46
Figure 3-3. Susitna Watershed Lower River Segment, with geomorphic reaches indicated (Source:
ISR Study 7.5, Figure 3-3). .................................................................................................... 47
Figure 4.5-1. FA-128 (Slough 8A) Focus Area with groundwater and surface water monitoring
locations (Source: ISR Study 7.5, Appendix B, Figure 3-3). ................................................ 48
Figure 4.5-2. Groundwater Model Extent and Simulated Features in FA-128 Area (Source: ISR
Study 7.5, Appendix B, Figure 4-2). ..................................................................................... 49
Figure 5.4-1. Example delineation of Riverine Dominated, Riverine-Upland Transitional, and
Upland Dominated. (Source: SIR Study 7.5, Appendix D, presentation slide 30.) ............... 50
Figure 5.5-1. Primary riparian cross section at FA-115 (Slough 6A) showing location of
groundwater wells, surface-water measurement locations, and the measured water levels on
April 24-25, 2014, with inferred water table. (Source: GWS and R2 2014a - Figure 22.) .. 51
Figure 5.5-2. Groundwater elevations and surface-water levels for selected stations in FA-115
(Slough 6A) representing upland groundwater conditions and lower groundwater wells
affected by riverine processes. (Source: GWS and R2 2014a - Figure 23.) ......................... 51
Figure 5.5-3. Cross-section profile of the Upper Riparian Transect in FA-128 (Slough 8A)
showing the land surface profile, location of groundwater wells and surface water measuring
points on Upper Side Channel 8A and Slough 8A. Water levels are shown for the April 20-
23, 2014. Water levels in Upper Side Channel 8A are ice affected. (Source: GWS and R2
2014a - Figure 26.) ................................................................................................................ 52
Figure 5.5-4. Water level data for Upper Side Channel 8A, Slough 8A, and groundwater wells
between the two surface-water features on the Upper Riparian Transect in FA-128 (Slough
8A). (Source: GWS and R2 2014a - Figure 27.) .................................................................. 52
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Figure 5.5-5. Primary riparian cross section at FA-138 (Gold Creek) showing locations of surface-
water measurement locations, and typical upland features that indicate shallow groundwater
conditions. Water levels are shown for the cross-section survey date of 9/14/2014. (Source:
GWS and R2 2014a - Figure 24.) .......................................................................................... 53
Figure 5.5-6. Surface-water levels for stations in the FA-138 (Gold Creek) riparian transect. Major
hydrologic periods are indicated to show how the variation in water levels relate to the climate
and hydrologic processes relevant to these periods. (Source: GWS and R2 2014a - Figure 25.)
............................................................................................................................................... 53
Figure 5.5-7. Monitored versus Simulated Steady State Groundwater Elevations. (Source: SIR
Study 7.5, Appendix B, Figure 5-1.) ..................................................................................... 54
Figure 5.5-8. Simulated Steady Stage Groundwater Elevations and Model Target Residuals in FA-
128 Area. (Source: SIR Study 7.5, Appendix B, Figure 5-2.) .............................................. 55
Figure 5.5-9. Simulated Steady Stage Groundwater Elevations with Flooded and Dry Model Cells
Shown. (Source: SIR Study 7.5, Appendix B, Figure 5-3.) .................................................. 56
Figure 5.5-10. Monitored versus Simulated Steady State Groundwater Elevations (Station 128-
13). (Source: SIR Study 7.5, Appendix B, Figure 5-4.) ....................................................... 57
Figure 5.5-11. Monitored versus Simulated Steady State Groundwater Elevations (Station 128-4).
(Source: SIR Study 7.5, Appendix B, Figure 5-5.) ................................................................ 58
Figure 5.5-12. Monitored versus Simulated Transient Head Difference between Surface water and
Groundwater at Target Station 128-6. (Source: SIR Study 7.5, Appendix B, Figure 5-6.) .. 59
Figure 5.5-13. Monitored versus Simulated Transient Flux beneath Slough 8A at Target Station
128-6. (Source: SIR Study 7.5, Appendix B, Figure 5-10.) ................................................. 60
Figure 5.5-14. FA-104 (Whiskers Slough), showing water-level elevation contours for Late Fall
– October 9, 2013, Susitna River. (Source: SIR Study 7.5, Appendix A, Figure 5.1-3.) ..... 61
Figure 5.5-15. FA-115 (Slough 6A), showing water-level elevation contours for Late Fall –
October 9, 2013, Susitna River. (Source: SIR Study 7.5, Appendix A, Figure 5.2-2.) ........ 62
Figure 5.5-16. FA-128 (Slough 8A), showing water-level elevation contours for Late Fall –
October 9, 2013, Susitna River. (Source: SIR Study 7.5, Appendix A, Figure 5.3-3.) ........ 63
Figure 5.5-17. FA-138 (Gold Creek), showing water-level elevation contours for Late Fall –
October 9, 2014, Susitna River. (Source: SIR Study 7.5, Appendix A, Figure 5.4-2.) ........ 64
Figure 5.6-1. Groundwater Station ESGFA128-13 groundwater levels in wells adjacent to Middle
Side Channel 8A and surface-water stage in Middle Side Channel 8A, and groundwater levels
from wells at ESGFA128-20 and ESGFA128-21. (Source: GWS and R2 2014b - Figure 4.1-
14.) ......................................................................................................................................... 65
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Figure 5.6-2. Groundwater Station ESGFA128-13 groundwater temperature in wells adjacent to
Middle Side Channel 8A and surface-water temperature in Middle Side Channel 8A, and
groundwater temperature from wells at ESGFA128-20 and ESGFA128-21. (Source: GWS
and R2 2014b - Figure 4.1-15.) ............................................................................................. 65
Figure 5.6-3. Downwelling example in Middle Side Channel 8A in FA-128 (Slough 8A) showing
groundwater and surface-water levels, stream-bed temperatures, and thermal profile of the
stream bed conditions through the major hydrologic periods. (Source: GWS and R2 2014b -
Figure 4.3-32.) ....................................................................................................................... 66
Figure 5.6-4. Upwelling example in Upper Side Channel 11 in FA-138 (Gold Creek) showing
groundwater and surface-water levels, stream-bed temperatures, and thermal profile of the
stream bed conditions through the major hydrologic periods. (Source: GWS and R2 2014b -
Figure 4.3-33.) ....................................................................................................................... 67
APPENDICES
Appendix A: Preliminary Water Table Contour Maps for Focus Areas FA-104, FA-115, FA-128,
and FA-138
Appendix B: Preliminary MODFLOW Three Dimensional Groundwater Model for Focus Area
FA-128 (Slough 8A)
Appendix C: Summary Review of Susitna River Hydrogeologic Studies Conducted in the 1980s
and Other Non-Project Related Studies with Relevance to Proposed Susitna-Watana Dam
Project
Appendix D: December 5, 2014 Technical Team Meeting Notes and Presentation
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LIST OF ACRONYMS, ABBREVIATIONS, AND DEFINITIONS
Abbreviation Definition
AEA Alaska Energy Authority
ARLIS Alaska Resources Library and Information Services
ASTM American Society for Testing and Materials
cfs cubic feet per second
FA Focus Area
FDAML Fish Distribution and Abundance in the Middle and Lower River Study (Study 9.6)
FERC Federal Energy Regulatory Commission
ft feet
GINA Geographic Information Network of Alaska
GW Groundwater
GWS Geo-Watersheds Scientific
HSC Habitat Suitability Criteria
HSI Habitat Suitability Index
IFS Instream Flow Study (Study 8.5)
ILP Integrated Licensing Process
ISR Initial Study Report
OWFRM Open-water Flow Routing Model
PHABSIM Physical Habitat Simulation
PRM Project River Mile
QC Quality Control
RIFS Riparian Instream Flow Study (Study 8.6)
RSP Revised Study Plan
SIR Study Implementation Report
SPD Study Plan Determination
SW Surface Water
TIR Thermal Infrared
TM Technical Memorandum
USGS United States Geological Survey
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1. INTRODUCTION
This Groundwater (GW) Study, Section 7.5 of the Revised Study Plan (RSP) (AEA 2012)
approved by the Federal Energy Regulatory Commission (FERC) for the Susitna-Watana
Hydroelectric Project, FERC Project No. 14241, focuses on providing an overall understanding of
Groundwater (GW)/Surface Water (SW) interactions at both the watershed- and local-scales. This
understanding will be used in evaluating Project operational effects on GW/SW interactions and
resulting effects on riparian and aquatic habitats.
A summary of the development of this study, together with the Alaska Energy Authority’s (AEA)
implementation of it through the 2013 study season, appears in Part A, Section 1 of the Initial
Study Report (ISR) filed with the FERC in June 2014 (AEA 2014). As required under the FERC’s
regulations for the Integrated Licensing Process (ILP), the ISR describes AEA’s “overall progress
in implementing the Study Plan and schedule and the data collected, including an explanation of
any variance from the Study Plan and schedule.” (18 CFR 5.15(c)(1)).
Since filing the ISR in June 2014, AEA has continued to implement the FERC-approved Study
Plan for the GW Study. For example:
Data collection has continued via a combination of telemetered wells, self-logging
temperature and water level recorders and remote cameras, In addition, quality control
(QC) checks of existing data have continued resulting in QC3 level data being made
available to other resource users. The QC3 analysis was on data (water levels, water
temperature, geotechnical and/or water-surface elevations) that were downloaded in 2014
from manual and telemetered installations as well as telemetered data received up through
July 31, 2015.
Two Technical Memoranda were prepared and submitted in September 2014 that presented
results of preliminary GW/SW analysis related to GW Study Objective 5 that pertains to
the Riparian Instream Flow Study (RIFS) (Study 8.6) and GW Study Objective 6 that
pertains to the Fish and Aquatics Instream Flow Study (IFS) (Study 8.5). These included
the following:
o Groundwater and Surface-Water Relationships in Support of Riparian Vegetation
Modeling – Technical Memorandum submitted to the FERC September 30, 2014
(GWS and R2 2014a)
o Preliminary Groundwater and Surface-Water Relationships in Lateral Aquatic
Habitats within Focus Areas FA-128 (Slough 8A) and FA-138 (Gold Creek) in the
Middle Susitna River – Technical Memorandum submitted to the FERC September
30, 2014 (GWS and R2 2014b)
Three technical reports have been prepared and are included as appendices to this Study
Implementation Report (SIR). Two of the reports describe further analysis of GW data
including development of a series of water table maps for respective Focus Areas, and
development and application of a preliminary MODFLOW GW model for FA-128 (Slough
8A). The third report provides a literature review of the 1980s GW studies and some
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additional contemporary relevant information pertaining to GW/SW interactions. The
appendices include:
o Appendix A – Preliminary Water Table Contour Maps for Focus Areas FA-104,
FA-115, FA-128, and FA-138, submitted to the FERC November 2015 (PGG
2015a)
o Appendix B – Preliminary MODFLOW Three Dimensional Groundwater Model
for Focus Area FA-128 (Slough 8A), submitted to the FERC November 2015 (PGG
2015b)
o Appendix C – Summary Review of Susitna River Hydrogeologic Studies
Conducted in the 1980s and other Non-Project Related Studies with Relevance to
Proposed Susitna-Watana Dam Project, submitted to the FERC November 2015
(PGG 2015c)
On December 5, 2014 AEA held a Groundwater Study Technical Team Meeting to discuss
and solicit questions from Licensing Participants regarding the October 2014 ISR meetings
and on the two September 2014 TMs noted above. A meeting summary was subsequently
prepared and made available to the Licensing Participants on AEA’s public website. A
copy of the presentation materials and the meeting summary are included in this SIR Study
7.5, Appendix D (GWS 2015).
In furtherance of the next round of ISR meetings and the FERC Director’s Study Determination
expected in 2016, this SIR describes AEA’s overall progress in implementing the GW Study
through the end of calendar year 2014 and up through and including the submittal of this SIR in
2015. The SIR is not intended to provide a comprehensive reporting of all field work, data
collection, and data analysis since the beginning of AEA’s study program, but rather to provide an
update of information presented in ISR Part A for the GW Study. The SIR and its appendices
describe the methods and results of these efforts, and discuss the results in terms of the nine stated
objectives of the GW Study (Study 7.5). Although each of the nine objectives are included in the
SIR, only those for which substantial work was completed are discussed in detail.
2. STUDY OBJECTIVES
The nine study objectives of the GW Study (Study 7.5) as established in RSP Section 7.5.1 are as
follows:
1. Synthesize historical and contemporary GW data available for the Susitna River GW and
GW dependent aquatic and floodplain habitat, including that from the 1980s and other
studies including reviews of GW/SW interactions in cold regions (RSP Section 7.5.4.1.1).
2. Use the available GW data to characterize large-scale geohydrologic process-
domains/terrain of the Susitna River (e.g., geology, topography, geomorphology, regional
aquifers, shallow GW aquifers, GW/SW interactions) (RSP Section 7.5.4.1.2).
3. Assess the potential effects of Watana Dam/Reservoir on GW and GW-influenced aquatic
habitats in the vicinity of the proposed dam (RSP Section 7.5.4.2).
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4. Work with other resource studies to map GW-influenced aquatic and floodplain habitat
(e.g., upwelling areas, springs, GW-dependent wetlands) within the Middle River Segment
of the Susitna River including within selected Focus Areas (IFS Study 8.5) (RSP Section
7.5.4.3).
5. Determine the GW/SW relationships of floodplain shallow alluvial aquifers within selected
Focus Areas as part of the RIFS (Study 8.6) (RSP Section 7.5.4.4).
6. Determine GW/SW relationships of upwelling/downwelling in relation to spawning,
incubation, and rearing habitat (particularly in the winter) within selected Focus Areas as
part of the IFS (Study 8.5) (RSP Section 7.5.4.5).
7. Characterize water quality (e.g., temperature, dissolved oxygen, conductivity) of selected
upwelling areas that provide biological cues for fish spawning and juvenile rearing, in
Focus Areas as part of the IFS (Study 8.5) (RSP Section 7.5.4.6).
8. Characterize the winter flow in the Susitna River and how it relates to GW/SW interactions
(RSP Section 7.5.4.7).
9. Characterize the relationship between the Susitna River flow regime and shallow GW users
(e.g., domestic wells) (RSP Section 7.5.4.8).
3. STUDY AREA
As established by RSP Section 7.5.3, the study area related to GW processes includes primarily
the Middle River Segment of the Susitna River that extends from Project River Mile (PRM) 102.4
to PRM 187.1 as well as portions of the Lower River Segment associated with domestic wells and
riparian transect locations in the Lower River Segment, and the lower most portion of the Upper
River Segment near the proposed dam site associated with potential GW changes relative to
reservoir construction and operations. Figure 3-1 shows these river segments and the general
watershed boundary of the Susitna River. Figure 3-2 shows the location of Instream Flow Program
(Studies 8.5 and 8.6) Focus Areas and geomorphic reaches for the Middle River Segment. Figure
3-3 shows the Lower River Segment with the geomorphic reaches defined.
Following the completion of the Open-water Flow Routing Model (OWFRM) in Q1 2013, the
study areas for the riparian studies, including the riparian vegetation study, was extended to PRM
29.9. This increase in RIFS activities in the Lower River Segment was supported by the GW
Study.
4. METHODS
The GW Study is divided into nine study components related to the study objectives outlined in
Section 2 above: (1) existing data synthesis, (2) geohydrologic process-domains and terrain; (3)
Watana Dam/Reservoir, (4) upwelling/springs broad-scale mapping, (5) riparian vegetation
dependency on GW/SW interactions, (6) fish habitat GW/SW interactions, (7) water quality in
selected habitats, (8) winter GW/SW interactions, and (9) shallow GW users. Each of the
components and its related study methods have been explained in ISR Part A, Study 7.5 Section
4. This section provides an update of activities related to each of the objectives that have occurred
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since the June 2014 ISR. Only objectives for which work has been completed since June 2014 are
discussed in detail; others are cross-referenced back to the methods in the ISR.
4.1. Existing Data Synthesis
Since the June 2014 ISR, AEA has completed the review of literature and prepared a document
that summarizes the information in Appendix C. For this, the Alaska Resources Library and
Information Services (ARLIS) database was queried for reports for the Susitna River prior to the
ongoing studies. The terms Susitna hydrogeology, geohydrology, hydrology, geology, and ice
were searched, with the subject terms chosen with the intent of identifying reports likely to contain
data relating to the following five hydrogeologic concepts/properties that are important for
understanding GW/SW interactions within the Susitna River:
Aquifer extent and thickness
Aquifer properties (transmissivity, hydraulic conductivity, and storage)
Horizontal GW gradients and flow direction
Nature and extent of vertical GW gradients along the Susitna River
Groundwater and SW interactions within the Susitna River valley
A total of 278 document matches were obtained from ARLIS, and documents that were
electronically available and had potentially relevant titles were downloaded. Report table of
contents were then reviewed to assess if relevant hydrogeologic data were likely present in the
report. If relevant data appeared to be present, sections of the report with hydrogeologic data were
reviewed. In some instances older reports were superseded by younger reports (as in the case of
draft and final reports, or seasonal/single year data reports versus multi-year reports with an
overlapping timespan), and in these cases the more recent reports were reviewed. The information
obtained from ARLIS was supplemented via targeted Internet searches for studies concerned with
evaluating changes to GW/SW interactions due to hydroelectric developments in cold regions.
The information obtained from the review and preparation of the literature review document
(Appendix C) is expected to benefit current and future GW studies by compiling existing
hydrogeologic data (or reference to it) within one document and highlighting previous studies that
current resource investigators may be unaware of.
4.1.1. Variances
AEA implemented the methods as described in the Study Plan with no variances. With the
preparation of the Summary Review of Susitna River Hydrogeologic Studies Conducted in the
1980s and other Non-Project Related Studies with Relevance to Proposed Susitna-Watana Dam
Project presented as Appendix C to this SIR, the objective of this particular component of the GW
study has been met.
4.2. Geohydrologic Process-Domains
As described in ISR Study 7.5, Section 4.2, AEA implemented the methods associated with this
study element in accordance with the Study Plan. However, there has been no substantive activity
on this element since completion of the June 2014 ISR.
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4.2.1. Variances
AEA implemented the methods as described in the Study Plan with exception of the variance
mentioned in ISR Study 7.5, Section 4.2.1 regarding the schedule:
The schedule for completion of the mapping of geohydrologic units and associated analysis
will be completed once all of the necessary information has been assembled and reviewed.
4.3. Watana Dam/Reservoir
As described in ISR Study 7.5, Section 4.3, AEA implemented the methods associated with this
study element in accordance with the Study Plan. There has been no substantive GW specific
activity on this element since completion of the June 2014 ISR. However, AEA has continued
Project Engineering Feasibility Studies Geotechnical Investigations, and the Geology and Soils
Characterization Study (Study 4.5) since the June 2014 ISR; (see SIR Study 4.5 for description of
work). Results of those investigations will be used in part to evaluate the GW conditions in the
Project area and evaluate the potential for GW impacts downstream of the dam.
4.3.1. Variances
AEA implemented the methods as described in the Study Plan with no variances.
4.4. Upwelling / Springs Broad-Scale Mapping
AEA implemented the methods as described in the Study Plan with no variances. Since completion
of the June 2014 ISR, the primary activity on this element has been associated with the
differentiation of upwelling areas within FA-128 (Slough 8A) into three categories: Riverine
Dominated, Riverine – Upland Transitional, and Upland Dominated. These categories were
derived from a combination of data sources that included photographs taken during the winter that
depicted areas of open-water leads, aerial photography and aerial videography of the ice-free
period showing turbid and clear water habitats, and thermal infrared imagery (TIR) collected in
October 2012 and October 2013 (see ISR Study 5.5, Appendix J, TIR Images submitted to the
FERC June 3, 2014 [Tetra Tech 2014] for detailed results of the TIR mapping).
AEA is applying the same general process for identifying GW areas throughout the entire Middle
River Segment of the Susitna River. Results of that analysis will be available at the end of 2015.
4.4.1. Variances
AEA implemented the methods as described in the Study Plan with no variances.
4.5. Riparian Vegetation Dependency on Groundwater / Surface-
Water Interactions
AEA implemented the methods as described in the Study Plan and further detailed in the ISR (ISR
Study 7.5, Section 4.5), with the exception of variances described below (Section 4.5.1). Since
the June 2014 ISR, AEA has completed the following GW related activities associated with
meeting this objective: preparation and submittal of a Technical Memorandum (TM) describing
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preliminary analysis of GW/SW interactions supportive of the RIFS (Study 8.6) (GWS and R2
2014a), completion of a Technical Team Meeting as a follow-up to questions raised during the
October 2014 ISR meeting (Appendix D), development of a preliminary MODFLOW GW model
for FA-128 (Slough 8A) (Appendix B), development of a time-series of water table maps for
selected Focus Areas (Appendix A), and the continued collection of data from within selected
Focus Areas as well as at selected locations in the Lower River Segment. These activities are
described further below.
4.5.1. Preparation and Submittal of Technical Memorandum – GW/SW
Relationships to Support Riparian Vegetation Modeling
Since the June 2014 ISR, AEA completed a preliminary analysis of 2013 and 2014 data to illustrate
GW/SW relationships within various Focus Areas and their influence on riparian vegetation. The
results of the analysis were presented in a TM (GWS and R2 2014a) and discussed in part during
a Technical Team Meeting on December 5, 2014 (Section 4.5.3). The TM provided a status update
concerning general 2014 GW/SW data collection activities in support of RIFS, and presented
GW/SW analyses and results using FA-115 (Slough 6A) as a primary example, with additional
analyses presented for FA-128 (Slough 8A) and FA-138 (Gold Creek).
4.5.2. Groundwater Technical Team Meeting
On December 5, 2014, AEA convened a Groundwater Technical Team Meeting as a follow-up to
the October 2014 ISR meetings. The meeting served to address a variety of questions raised during
the ISR meeting related to the overall GW Study, and included a discussion of the TM noted above.
The presentation materials and meeting notes associated with the meeting are included as
Appendix D to this SIR.
4.5.3. Preliminary Three-dimensional MODFLOW Model for FA-128 (Slough 8A)
Since the June 2014 ISR, AEA has developed a preliminary three dimensional MODFLOW model
(MODFLOW) for FA-128 (Slough 8A) following the methods specified in the GW Study Plan
(RSP Section 7.5.4.4). Selection of FA-128 for model development was consistent with earlier
resource studies that utilized FA-128 as part of the Proof of Concept demonstrations (ISR Study
8.5, Appendix N, Middle River Fish Habitat and Riverine Modeling Proof of Concept submitted
to the FERC June 3, 2014 [R2 2014a]) Model code selection and calibration procedures followed
American Society for Testing and Materials (ASTM) standard D6170 (ASTM 2010) and D5981
(ASTM 2008) respectively. Specified snowmelt runoff stage-change events from the 2014
monitoring period were used to develop and perform preliminary model calibrations and to
demonstrate evaluations of GW/SW interactions critical for riparian and aquatic habitat. The
MODFLOW model was designed and calibrated to data collected from field stations within FA-
128 (Slough 8A) during 2014 (Figure 4.5-1).
The total domain of the model covers approximately 18.2 square miles, with the active part of the
domain representing the alluvial aquifer within the Susitna River floodplain from approximately
PRM 126.4 to 131.7 (Figure 4.5-2). Focus Area FA-128 (Slough 8A) extends from PRM 128.1 to
129.7; however, the model was extended another 1.5 miles upgradient and 1.5 miles downgradient
of the upper and lower boundaries of the Focus Area to set far field general head boundary
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conditions that would not influence the result of the simulation in the Focus Area. The model
domain also extends about 1.5 miles to the northwest and 1.5 miles to the southeast beyond the
Susitna River floodplain towards local topographic divides. Although this area of the model is
currently inactive, the extension of the domain to beyond the Susitna River floodplain will allow
for the future simulation of the regional GW flow system if/when data become available. The
active model domain (simulated alluvial aquifer within the Susitna River floodplain from PRM
126.4 to 131.7) covers approximately 3.3 square miles.
The preliminary MODFLOW model includes both a steady state and a transient model. The steady
state model was developed first to simulate average “baseflow” conditions (i.e., when little
flooding is occurring in the Susitna River and side channels are predominantly fed by GW).
Calibration of the steady state model was performed by adjusting aquifer parameters to best match
target GW elevations measured in FA-128 (Slough 8A). The solution to the steady state model
was then used as the initial GW condition at the start of the transient model. The transient model
was developed to simulate a time-varying flooding event during the 2014 period and associated
changes in GW gradients and fluxes. The transient model was run, and compared to observed
aquifer responses. Some limited transient calibration was achieved by varying the aquifer storage
coefficient term but additional calibration efforts will be needed to further test model performance
and make adjustments once additional data are incorporated into the model. The transient
simulation only involved changing the model river stages during discrete stress periods in the
simulation. All other model parameter values were held constant. Details regarding the calibration
and preliminary outputs of the MODFLOW model are presented in Section 5.4; the model is fully
described in Appendix B.
4.5.4. Water Table Maps
AEA has also prepared a time series of water table maps for four Focus Areas (FA-104 [Whiskers
Slough], FA-115 [Slough 6A], FA-128 [Slough 8A], and FA-138 [Gold Creek]), that depict GW
elevations under different seasonal flow conditions. Example maps for each of these areas for a
single time period were presented and discussed during the December 5, 2014 Technical Team
Meeting (Appendix D) and proved useful for spatially depicting GW levels over the entire Focus
Area and for potentially differentiating riverine versus upland dominated categories of GW. To
expand that analysis, a total of six maps corresponding to six different time periods were developed
for FA-104 (Whiskers Slough) and FA-128 (Slough 8A), three maps corresponding to three time
periods were developed for FA-138 (Gold Creek), and two maps corresponding to two periods
were developed for FA-115 (Slough 6A). The time periods were selected to be representative of
conditions during the Fall (September 13, 2013), Late Fall (October 9, 2013), Ice Cover/Ice Jam
(February 20, 2014), Pre-breakup (April 20, 2014), Post-breakup (July 11, 2014), and Summer
(August 13, 2014) conditions.
The number of maps developed for each Focus Area was based in part on the availability of GW
data from the respective network of wells within each area, and the relative number of time steps
needed to evaluate important biological functions occurring in each. For example, both FA-104
(Whiskers Slough) and FA-128 (Slough 8A) support important fish life history functions on a year-
round basis including spawning (Fall and Late Fall), egg incubation and overwintering juvenile
rearing (Late Fall, Ice Cover/Ice Jam, Pre-breakup), and fry emergence, juvenile rearing, and smolt
outmigration (Post-breakup and Summer). In comparison, FA-115 (Slough 6A) contains primarily
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juvenile rearing habitat which can be limiting during the Late Fall (low flow) and Post-breakup
(relatively high flow) periods.
Selection of representative dates for the open-water periods was based on a review of flow records
for United States Geological Survey (USGS) Gage on the Susitna River at Gold Creek (Gage No.
15292000). The Post-breakup and Fall dates represent higher flows and the Late Fall and Summer
dates represent relatively low flows. The date selected for Summer conditions included diurnal
glacial melt fluctuations. Selection of dates during the ice covered period was based on a review
of discharge measurements during those periods that coincided with GW well data. The Ice
Cover/Ice Jam date coincided with development of an ice jam and flooding of lateral habitats
within FA-128 (Slough 8A); the Pre-breakup date represented a relatively low flow under ice
condition. The specific dates selected for the respective Focus Areas are depicted in Table 4.5-1.
4.5.5. Continuation of Data Collection and QC3 Data Review
Groundwater related data have continued to be collected via a combination of telemetered wells,
self-logging temperature and water level recorders placed in non-telemetered wells, and remote
time-lapse cameras. These data are being collected within Focus Areas FA-104 (Whiskers Slough)
(ISR Study 7.5, Figure 4.5-6), FA-113 (Oxbow 1) (ISR Study 7.5, Figure 4.5-5), FA-115 (Slough
6A) (ISR Study 7.5, Figure 4.5-4), FA-128 (Slough 8A) (ISR Study 7.5, Figure 4.5-3), and FA-
138 (Gold Creek) (ISR Study 7.5, Figure 4.5-2), as well as within five stations in the Lower River
Segment (ISR Study 7.5, Figures 4.5-8 through 4.5-11) that were established to support the RIFS
(Study 8.6).
Some of the recording stations have been damaged due to high flows and debris, ice flows and ice
jacking and have stopped recording/reporting. AEA has conducted a review and evaluation of the
damaged stations and has completed a field operation to remove damaged equipment and
equipment no longer needed (i.e., equipment that was installed to support data collection tasks that
are complete – e.g., sap flow meters), and to service and repair high priority stations. Table 4.5-2
has been adapted from the ISR Study 7.5, Tables 4.5-1 to 4.5-4 to provide a listing and a current
status report of all of the stations previously installed to support this objective.
In addition to data collection, AEA has continued the data Quality Assurance/Quality Control
(QA/QC) review process resulting in QC3 level data being made available to other resource users.
The QC analysis was completed on data (water levels, water temperature, geotechnical and/or
water-surface elevations) that have been downloaded in 2014 from manual and telemetered
installations as well as telemetered data received up through July 31, 2015 whose values were
consistent with prior data from the same stations (i.e., indicating no station impairment). Table
4.5-3 summarizes the overall status of QC3 data that have been delivered to Geographic
Information Network of Alaska (GINA) and are publically available.
4.5.6. Variances
AEA implemented the methods as described in the Study Plan with the exception of a variance
related to the schedule for development of GW models that was noted in the June 2014 ISR (Study
7.5, Section 4.5.1). However, since then a preliminary MODFLOW GW model has been
developed for FA-128 (Slough 8A) and is described in Appendix B. The model has been structured
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to allow its integration with other resource models and will be applicable for evaluating Project
operational effects on GW/SW relationships within Focus Areas. Importantly, the methods and
techniques utilized in development of the MODFLOW model for FA-128 (Slough 8A) can be
applied in the development of MODFLOW models at other Focus Areas including FA-104
(Whiskers Slough), FA-115 (Slough 6A), and FA-138 (Gold Creek). Since the June 2014 ISR, a
series of water table maps have also been developed for FA-104 (Whiskers Slough), FA-115
(Slough 6A), FA-128 (Slough 8A), and FA-138 (Gold Creek). The water table maps will be useful
for spatially depicting GW levels and identifying areas of potential model parameter heterogeneity
in areas with sufficient well density.
4.6. Aquatic Habitat Groundwater / Surface-Water Interactions
AEA implemented the methods as described in the Study Plan with the exception of variances
explained below (Section 4.6.1). The same general approach as described above for the riparian
component is being used for evaluating GW/SW interactions within aquatic habitats as part of the
IFS (Study 8.5). Since the June 2014 ISR, AEA has completed the following GW related activities
associated with meeting this objective: preparation and submittal of a TM describing preliminary
analysis of GW/SW interactions supportive of the IFS (Study 8.5) (GWS and R2 2014b);
completion of a Technical Team Meeting on December 5, 2014 as a follow-up to questions raised
during the October 2014 ISR meeting (Appendix D); development of a preliminary MODFLOW
GW model for FA-128 (Slough 8A) (Appendix B); development of a time-series of water table
maps for selected Focus Areas (Appendix A); and the continued collection of data from within
selected Focus Areas as well as at selected locations in the Lower River Segment. These activities
are described further below.
4.6.1. Preparation and Submittal of Technical Memorandum – GW/SW
Relationships in Lateral Aquatic Habitats
Since the June 2014 ISR, AEA completed a preliminary analysis of 2013 and 2014 data to illustrate
GW/SW relationships within various Focus Areas and their influence on lateral aquatic habitats.
The results of the analysis were presented in a TM (GWS and R2 2014b) and discussed in part
during a Technical Team Meeting on December 5, 2014 (Section 4.5.3). The TM provided a status
update concerning general 2014 GW/SW data collection activities in support of the IFS (Study
8.5), and presented GW/SW analyses and results using FA-128 (Slough 8A) as a primary example,
with additional analyses presented for FA-138 (Gold Creek).
4.6.2. Groundwater Technical Team Meeting
On December 5, 2014, AEA convened a Groundwater Technical Team Meeting as a follow-up to
the October 2014 ISR meetings. The meeting served to address a variety of questions raised during
the ISR meeting related to the overall GW Study, and included a discussion of the TM noted above.
The presentation materials and meeting notes associated with the meeting are included as
Appendix D to this SIR.
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4.6.3. Preliminary Three-dimensional MODFLOW Model for FA-128
As described in Section 4.5.3 above, since the June 2014 ISR, AEA has developed a preliminary
three dimensional MODFLOW model (MODFLOW) for FA-128 (Slough 8A) following the
methods specified in the GW Study Plan (RSP Section 7.5.4.4). Selection of FA-128 for model
development was consistent with earlier resource studies that utilized FA-128 as part of the Proof
of Concept demonstrations (ISR Study 8.5, Appendix N [R2 2014a]). Development of the
MODFLOW GW model for FA-128 will be particularly important for evaluating Project effects
on important GW upwelling areas that are biologically significant for spawning and egg
incubation. Output from the MODFLOW model can be linked with the PHABSIM 2D Habitat
Models that have incorporated “Upwelling” as one of the metrics in the Habitat Suitability Criteria
(HSC) (SIR Study 8.5, Section 4.5 and Appendix D) for evaluating Project operational effects on
spawning and incubation habitats. Specifically, GW response functions can be developed from
the MODFLOW output as analytical expressions which can be used to quantify the predicted
changes in GW fluxes due to different scenarios of project operations. Project induced changes to
GW temperatures that are important for overwintering egg incubation can also be evaluated with
model output but will require additional model refinement.
Details regarding the development, calibration and preliminary outputs of the MODFLOW model
are presented in Appendix B.
4.6.4. Water Table Maps
AEA also prepared a time series of water table maps for four Focus Areas FA-104 (Whiskers
Slough), FA-115 (Slough 6A), FA-128 (Slough 8A), and FA-138 (Gold Creek) that depict GW
elevations under different seasonal flow conditions. As described in Section 4.5.4, a total of six
maps corresponding to six different time periods were developed for FA-104 (Whiskers Slough)
and FA-128 (Slough 8A), three maps corresponding to three time periods were developed for FA-
138 (Gold Creek), and two maps corresponding to two periods were developed for FA-115 (Slough
6A). The time periods were selected to be representative of conditions during the Fall (September
13, 2013), Late Fall (October 9, 2013), Ice Cover/Ice Jam (February 20, 2014), Pre-breakup (April
20, 2014), Post-breakup (July 11, 2014), and Summer (August 13, 2014) conditions. The water
table maps will be important for evaluating changes in GW levels under different river stage
conditions within important fish habitats in the lateral margins of the Susitna River including side
channels, side sloughs and upland sloughs.
4.6.5. Continuation of Data Collection and QC3 Data Review
As noted in Section 4.5.5, GW related data have continued to be collected via a combination of
telemetered wells, self-logging temperature and water level recorders placed in non-telemetered
wells, and remote time-lapse cameras.
In addition, AEA collected a series of discharge measurements over a five day period in September
(September 23-27, 2014) within various lateral habitats and at tributary mouths in seven Focus
Areas, including FA-104 (Whiskers Slough), FA-115 (Slough 6A), FA-128 (Slough 8A), FA-138
(Gold Creek), FA-141 (Indian River) and FA-144 (Slough 21). These measurements were
conducted as part of a joint effort between the IFS (Study 8.5) and Geomorphology Modeling
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(Study 6.6) and were designed to occur during a relatively low-flow period in the Susitna River.
Flows in the Susitna River as measured at the Gold Creek Gage (No. 15292000) ranged from
around 17,000 cubic feet per second (cfs) on September 23 to 12,500 cfs on September 27. The
discharge measurements provided data that will be useful for refining the distribution of flows
within the respective channels in the SRH-2D model grid, and also for understanding GW
contributions. Additional details concerning this data collection effort are presented in the
Geomorphology Modeling (Study 6.6) SIR in Section 5.1.2.4.
In addition to data collection, AEA has continued the data QA/QC review process resulting in QC3
level data being made available to other resource users.
4.6.6. Variances
AEA implemented the methods as described in the Study Plan with the exception of a variance
related to the schedule for development of GW models that was noted in the June 2014 ISR (Study
7.5, Section 4.5.1). However, since then a preliminary MODFLOW GW model has been
developed for FA-128 (Slough 8A) and is described in Appendix B. The model has been structured
to allow its integration with other resource models and will be applicable for evaluating Project
operational effects on GW/SW relationships within Focus Areas. Importantly, the methods and
techniques utilized in development of the MODFLOW model for FA-128 can be applied in the
development of MODFLOW models at other Focus Areas including FA-104 (Whiskers Slough),
FA-115 (Slough 6A), and FA-138 (Gold Creek).
4.7. Water Quality in Selected Habitats
AEA implemented the methods as described in the Study Plan and ISR Study 7.5, Section 4.7, ISR
Study 5.5, Section 4.4.2 and ISR Study 8.5, Sections 4.5.1.5, 4.5.1.6 and 4.5.1.10. The overall
objective of this work was to evaluate water quality characteristics within areas that may be
influenced by GW and that are known to be biologically important for fish (e.g., spawning and
incubation). Since the June 2014 ISR, AEA has completed several tasks to meet this objective.
First, as part of Study 8.5 and in response to the FERC Study Plan Determination (SPD) (Pages B-
84-B-86 of April 1, 2013 SPD [FERC 2013]), AEA completed a detailed evaluation of the
relationship between fish abundance and specific microhabitat variables that included several
water quality parameters (water temperature, dissolved oxygen, pH, alkalinity, macronutrients,
dissolved organic carbon, as well as surface-groundwater exchange flux) and reported results in a
TM titled Evaluation of Relationships between Fish Abundance and Specific Microhabitat
Variables, submitted to the FERC September 17, 2014 (R2 2014b). AEA has also, as part of Study
8.5 HSC analysis (ISR Study 8.5, Section 4.5), continued the collection and analysis of ancillary
water quality data (dissolved oxygen, water temperature and conductivity) from SW locations
some of which are influenced by GW upwelling, and from continuous temperature (surface and
intergravel) and dissolved oxygen (intergravel) recorders placed in Focus Areas with known
spawning activity (FA-104 [Whiskers Slough], FA-128 [Slough 8A], FA-138 [Gold Creek] and
FA-144 [Slough 21]). The dissolved oxygen monitors were deployed prior to spawning and have
recorded data throughout the egg incubation and fry emergence periods that has included winter
under ice conditions. The dissolved oxygen monitors were serviced in September 2015 and have
been redeployed to continue collecting data over the 2015-2016 winter period. Further discussion
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related to the analyses of water quality data in Focus Areas are presented in SIR Study 8.5,
Appendix A and Appendix D, and SIR Study 8.5, Sections 5.5 and 6.5. In addition and more
broadly, the Baseline Water Quality Study (Study 5.5) has prepared a Study Completion Report
(SCR Study 5.5). That report includes the results of the water quality sampling that was conducted
in the Focus Areas in SWs and in selected GW wells.
4.7.1. Variances
AEA implemented the methods as described in the Study Plan with no variances. As described
above, the objective of this particular component of the GW Study has been met.
4.8. Winter Groundwater / Surface-Water Interactions
AEA implemented the methods as described in the Study Plan with no variances. The objective
of this study element was to characterize the winter flow in the Susitna River and how it relates to
GW/SW interactions.
Since the June 2014 ISR, AEA has continued to collect and analyze winter data from GW wells
and SW recording stations in FA-104 (Whiskers Slough), FA-113 (Oxbow 1), FA-115 (Slough
6A), FA-128 (Slough 8A), and FA-138 (Gold Creek). The time-lapse cameras installed within
Focus Areas have also continued to capture images of main channel and lateral habitats under
varying flow under varying seasonal conditions.
Data collected as part of the coordinated 2014 winter studies were evaluated and presented and
discussed as part of the September TM pertaining to GW/SW relationships in lateral habitats
(GWS and R2 2014b). Those data consisted of winter discharge measurements collected during
three time periods within various Focus Areas. Measurements made during the first two periods,
March 3-16, 2014 and April 1-13, 2014 were collected at selected locations in FA-104 (Whiskers
Slough), FA-128 (Slough 8A) and FA-138 (Gold Creek). Measurements were recorded in open-
water and ice covered areas within side channel, side slough and upland slough habitats. Discharge
was measured at eight locations in FA-104 (Whiskers Slough), five locations in FA-128 (Slough
8A) and at six sites in FA-138 (Gold Creek). Measurement locations were established in habitats
with substantial GW influence and known fish habitat use during winter. An additional series of
end-of-winter discharge measurements to document GW recharge or discharge in SW features
were made from April 16-26, 2014 in the same three Focus Areas noted above. For those
measurements, channel sections were chosen that had no or minimal ice and snow conditions, so
an open channel measurement could be made. Paired measurements were made in select areas to
measure the difference in discharge for certain channel reaches. Because the goal of these
measurements was to measure small differences in GW for GW recharge to the sloughs or side
channels, triplicate measurements were made at some locations when field logistics allowed. The
winter discharge data will be useful in the calibration process of the River1D and River2D Ice
Processes models (Study 7.6). These models will be used in part for evaluating Project effects on
stage and flow distributions within lateral habitats under ice covered conditions.
When linked, the River1D and River2D Ice Processes models and the MODFLOW GW models
(Section 4.5) will be able to evaluate Project operational effects on GW/SW interactions during
the winter ice covered periods. Outputs from these models will be combined with the HSC/Habitat
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Suitability Index (HSI) curves and input to the 2D – PHABSIM Fish Habitat models to calculate
habitat quantities by species and life stage under different winter-time flow conditions (ISR Study
8.5, Section 5.6). Information collected as part of the IFS (Study 8.5) and Fish Distribution and
Abundance in the Middle and Lower River (FDAML) (Study 9.6) winter studies will be used in
part to support development of the HSC/HSI curves used for the modeling. The IFS (Study 8.5)
winter studies, specified in RSP Section 8.5.4.5.1.2.1, was specifically designed to evaluate
potential relationships between mainstem Susitna River stage and the quality and quantity of
winter aquatic habitats that support embryonic, juvenile, and adult life stages of fish species and
to record fish behavior and habitat utilization in support of HSC/HSI development (AEA
2012). The FDAML (Study 9.6) winter effort, described in RSP Section 9.6.4.5, was developed
to describe winter ecology of fish species in the Middle and Lower Susitna River (AEA
2012). Detailed results of the IFS and FDAML winter studies were presented as part of ISR Study
8.5, Appendix L, 2012-2013 Instream Flow Winter Pilot Studies, submitted to the FERC June 3,
2014 (R2 2014c) and ISR Study 9.6, Appendix C, Winter Sampling Report (2012-2013) submitted
to the FERC June 3, 2014 (R2 and LGL 2014a) and as Technical Memoranda (2013-2014 Instream
Flow Winter Studies submitted to the FERC September 17, 2014 [R2 2014d] and 2013-2014
Winter Fish Study submitted to the FERC September 17, 2014 [R2 and LGL 2014b]).
4.8.1. Variances
AEA implemented the methods as described in the Study Plan with no variances.
4.9. Shallow Groundwater Users
AEA implemented the methods as described in the Study Plan with no variances. Since the June
2014 ISR, AEA continued to monitor several domestic private wells proximal to the Susitna River
as a means to characterize the relationship between Susitna River flows and GW levels in the wells.
A total of four wells have been monitored including one at Gold Creek, two within FA-138 (Gold
Creek), and one near the Chase community area across from FA-104 (Whiskers Slough). The
wells have been monitored since 2013 and have provided a robust data set from which to evaluate
the relationship between Susitna River flow and water levels in the wells. AEA plans on
continuing to monitor the wells near Gold Creek but has removed the recorder from the Chase
Creek area.
4.9.1. Variances
AEA implemented the methods as described in the Study Plan with no variances.
5. RESULTS
Field data that has been QA/QC’d, and used in developing: 1) ISR Study 7.5; 2) Post-ISR TMs
(Groundwater and Surface-Water Relationships in Support of Riparian Vegetation Modeling TM
[GWS and R2 2014a] and Preliminary Groundwater and Surface-Water Relationships in Lateral
Aquatic Habitats within Focus Areas FA-128 [Slough 8A] and FA-138 [Gold Creek] in the Middle
Susitna River TM [GWS and R2 2014b]); and 3) SIR Study 7.5 are available on the GINA website
at the links below.
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http://gis.suhydro.org/isr/07-Hydrology/7.5-Groundwater/
http://gis.suhydro.org/Post_ISR/07-Hydrology/7.5-Groundwater/
http://gis.suhydro.org/SIR/07-Hydrology/7.5-Groundwater/
See Table 4.5-3 for a listing of data files pertaining to this SIR on the GINA website.
5.1. Existing Data Synthesis
Of the 278 documents initially identified, 18 were determined to contain information especially
relevant to GW/SW interactions, 12 of which contained findings of Project studies conducted
during the 1980s. These documents were summarized in the literature review (Appendix C) and
detailed information gleaned specific to each of the five categories of information:
Aquifer extent and thickness
Aquifer properties (transmissivity, hydraulic conductivity, and storage)
Horizontal groundwater gradients and flow direction
Nature and extent of vertical groundwater gradients along the Susitna River
Groundwater and surface water interactions within the Susitna River valley
Pertinent information available for each category from the documents was described and
summarized, and a table of aquifer properties was prepared (Table 5.1-1)
Overall, the hydrogeologic Project reports from the 1980s focused on documenting differences
between mainstem and slough temperatures and fluxes in an effort to predict slough flows under
post-Project conditions. Water levels in monitoring wells, sloughs, and the mainstem were also
documented to better understand slough upwelling flows. Based on detailed studies in Sloughs 9
and 8A, and to a lesser extent in Sloughs 11 and 21, it was concluded that many sloughs exhibit
differing and complex hydrologies (with flow regimes affected by tributaries, GW upwelling, berm
overtopping, and geologic/geomorphic features) that prevents simple regression relationships
between mainstem discharge and slough upwelling from being widely applicable. In general,
slough upwelling is affected by mainstem flows, but the relative amount of GW contribution to
slough flow can vary in time and space based on mainstem conditions and antecedent precipitation.
One of the conclusions of the studies (R&M Consultant and Woodward-Clyde 1985) was that
“Detailed projections cannot be made of the slough discharge or temperature variations which
might result from changes in mainstem conditions as a result of project operation. Because of the
substantial differences among the sloughs in their hydraulic and thermal behavior, it would be
necessary to construct mathematical models of each individual slough in order to make detailed
predictions of the effects on the sloughs of changes in mainstem conditions.” However, as part of
addressing GW Study (Study 7.5) Component 2 (Geohydrologic Domains), the differentiating
characteristics of sloughs (such as the presence of tributaries, upland soil/geology type, apparent
influence from mainstem flows, influence from overtopped-berm flows, etc.) will be reviewed
along with their hydrologic responses to see if sloughs with similar characteristics show similar
responses. If this is the case, the simulated results from the representative Focus Area sloughs that
are being modeled, could be extrapolated to other sloughs that are expected to have similar
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responses. Much of the water level and temperature data necessary for initial comparisons have
already been collected at multiple sloughs.
With the preparation of Appendix C, the objective of the existing data synthesis component of the
GW study has been met.
5.2. Geohydrologic Process-Domains
There has been no substantive activity on this element since completion of the June 2014 ISR.
5.3. Watana Dam/Reservoir
There has been no substantive GW related activity on this element since completion of the June
2014 ISR. However, AEA has continued Project Engineering Feasibility Studies Geotechnical
Investigations, and the Geology and Soils Characterization Study (Study 4.5) (see SIR Study 4.5
for description of work).
5.4. Upwelling / Springs Broad-Scale Mapping
As noted in Section 4.4, the primary activity on this element has been associated with the
differentiation of upwelling areas within FA-128 (Slough 8A) into three categories: Riverine
Dominated, Riverine-Upland Transitional, and Upland Dominated. An example delineation of
these categories was completed for FA-128 and presented during the December 5, 2014 Technical
Team Meeting (Figure 5.4-1).
As noted in Section 4.4, AEA is applying the same general process for identifying GW upwelling
areas throughout the entire Middle River Segment of the Susitna River, although differentiating
upwelling into the three categories will not be possible.
5.5. Riparian Vegetation Dependency on Groundwater / Surface
Water Interactions
Activities completed by AEA since the June 2014 ISR are described below.
5.5.1. Preparation and Submittal of Technical Memorandum – GW/SW
Relationships to Support Riparian Vegetation Modeling
The TM (GWS and R2 2014a) was prepared and submitted in September 2014. The TM described
analytical methods that are being employed for evaluating lateral hydraulic gradient relationships
and how those relationships would be used in assessing Project effects on riparian vegetation
communities. Examples of relationships were provided for FA-115 (Slough 6A), FA-128 (Slough
8A), and FA-138 (Gold Creek) and are depicted in Figures 5.5-1 and 5.5-2, Figures 5.5-3 and 5.5-
4, and Figures 5.5-5 and 5.5-6 respectively. These relationships illustrate differences between
upland dominated GW conditions that would be largely unaffected by Project operations and
riverine dominated conditions that would be directly influenced by Project operations.
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5.5.2. Groundwater Technical Team Meeting
A Groundwater Technical Team Meeting was conducted on December 5, 2014 as a follow-up to
the October 2014 ISR meetings and to discuss the two Technical Memoranda that were prepared
relative to the RIFS (Study 8.6) (see above) and IFS (Study 8.5) (Section 4.4.1) studies. The
presentation materials and meeting notes associated with the meeting are included as Appendix D
to this SIR.
5.5.3. Preliminary Three-dimensional MODFLOW Model for FA-128
A preliminary three dimensional MODFLOW model was successfully developed for FA-128
(Slough 8A). The model consisted of both a steady state model and a transient model. The steady
state model was developed to simulate average “baseflow” conditions in FA-128 (i.e., when little
flooding is occurring in the Susitna River and side channels are predominantly fed by GW). The
results of the steady state model were then used as starting GW conditions for the transient model
which was developed to simulate the spring melt flooding event in May 2014 and responses to
GW elevations, gradients between GW and SW, and fluxes between GW and SW.
The steady state model was calibrated to observed GW elevations and required little calibration
because steady state GW elevations are largely controlled by the assigned river stages in the model
(i.e., a relatively good calibration could be achieved with a range of aquifer parameters assigned
to the model). The transient model was partially calibrated against observed changes in GW
elevations and gradients between the GW and SW. The transient model calibration was limited to
adjustment of the aquifer storage coefficient parameter.
5.5.3.1. Steady State Model Calibration
The steady state model was calibrated to 14 observed GW elevations (targets) in FA-128 (Slough
8A) through trial and error (Table 5.5-1). Calibration focused primarily on adjustment of hydraulic
conductivity of the alluvial aquifer and the river bed sediments (Table 5.5-2). These values were
assumed to be spatially consistent throughout the model; however, future model refinements may
include incorporation of heterogeneity to improve model calibration. Other values that may be
varied in calibration include storage coefficient, anisotropy, river conductance, recharge, and
boundary conditions. These variables may also be varied spatially over the model. Future
calibration of these parameters would likely result in an improved simulations.
Specific fluxes along the sides of the model (regional GW subflow) were initially assigned a value
of 2.1 ft2/day per unit length of valley wall based on a previous rough estimate of regional GW
fluxes to the Susitna River valley (HESJV 1984), but was later reduced by an order of magnitude
to improve the overall calibration.
The best model fit to the GW elevation targets was achieved using a horizontal hydraulic
conductivity of 6 ft/day, a vertical hydraulic conductivity of 0.66 ft/day, and a river bed hydraulic
conductivity of 6 ft/day (Table 5.5-2). Figure 5.5-7 shows a plot of observed and simulated GW
elevations; a perfect fit would fall along the straight line. Figure 5.5-8 shows a map of the head
target locations and corresponding residuals (difference between simulated and observed GW
elevations). A negative residual value indicates the simulated GW elevation is too high and a
positive residual indicates it is too low. The target residuals were evenly divided between negative
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and positive values indicating the model does not trend towards over prediction or under prediction
of GW elevations. The absolute value of all target residuals was less than 1 foot, except at station
128-26 (3.25 feet) and station 128-4 (-1.37). The poorer fit of the model at these stations may
indicate the presence of aquifer heterogeneities not represented with the current model
configuration (Figure 5.5-8).
The simulated steady state GW elevations are strongly influenced by the assigned river stages in
the model and adjustments of the hydraulic conductivity of the aquifer and river bed sediments
resulted in only slight improvements or worsening of the overall calibration. A number of flooded
model cells occurred in layer 1 in the farfield area of the steady state model (Figure 5.5-9). Flooded
cells are areas where the simulated GW elevations are above the land surface and overestimate the
saturated thickness of the aquifer in layer 1. These are analogous to seeps or springs. The amount
of flooding ranged from less than 1 foot to about 10 feet in these areas. Future model refinements
can reduce flooded cells with the incorporation of the MODFLOW Drain Package, which
simulates GW seepage diversion from the aquifer.
A few dry cells also occurred in layer 1 near valley walls in the far field area of the model, but are
not expected to have much effect on the model results (Figure 5.5-9). Dry cells are areas where
the simulated GW elevations are below the bottom elevation of model layer 1. Future refinements
of the model may include additional model layers to refine simulation of vertical gradients in the
aquifer. Simulation of drying and rewetting model cells can be resolved during future refinements
of the model with the use of MODFLOW-NWT instead of the current MODFLOW-2000 code.
5.5.3.2. Transient Model Calibration
As noted in 4.5.3, some limited transient calibration was achieved by varying the aquifer storage
coefficient term within acceptable ranges to achieve a reasonable fit to the transient targets. Except
for the prescribed transient changes in river stages, all other model input parameters were held
constant from the calibrated best fit steady state model. The storage coefficient was initially set to
0.2, but was eventually reduced to a value of 0.001 to achieve a better match to the observed GW
elevation response. This value is somewhat low for an unconfined aquifer and may suggest the
aquifer is semi-confined.
The simulated transient changes in GW elevations were compared to observed changes at 15 target
locations (Table 5.5-1). The comparison shows the model generally obtained a good fit for target
stations located adjacent to simulated SW features (Figure 5.5-10), but targets further from the
river were less well matched (Figure 5.5-11); either the magnitude of the elevation change was off,
and/or the timing of the response was delayed. Despite the poor match to GW elevation changes
at some stations, the calibration statistics for the transient model were relatively good (Table 5.5-
2).
Like the steady state model, the transient model simulation also resulted in an increase in the
number of flooded model cells during the peak of the flooding event. As mentioned above, future
simulations can resolve flooded model cells with the use of the MODFLOW Drain Package
(Section 7.0).
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5.5.3.3. Simulated Transient Gradients and Fluxes
Output from the MODFLOW model can be used to quantify changes in vertical gradients and
fluxes between GW and SW during natural flooding events and some preliminary model runs were
completed to demonstrate this. However, additional model refinement and calibration will be
necessary before the model can be used to evaluate potential GW related impacts from different
Project operational scenarios on aquatic and floodplain habitats.
Plots of the monitored and simulated differences between GW elevations and adjacent SW stages
were made for four target stations (128-6, 128-7, 128-11, and 128-13) during a transient
simulation. The plots can be used to evaluate periods of upwelling and downwelling GW
responses before, during, and after the flooding event. At all stations, the simulated GW response
showed downwelling conditions prevailing during the flooding event as river stages increased
above the GW elevations in the underlying aquifer; Figure 5.5-12 depicts the plot for target station
128-6 and is provided for illustrative purposes (see Appendix B for all four target stations).
Following the peak flood event, the simulated downwelling conditions were followed by a
relatively quick change to upwelling conditions as the river stage dropped and GW drained back
into the river.
However, the observed GW response at a specific location differed somewhat from the simulated
response. The observed response at some stations showed upwelling conditions prevailing during
the initial flooding, which could be due to aquifer recharge from higher flooding stages upgradient
of that location. Alternatively, the observed GW response could be partly related to changes in
horizontal gradients since the monitoring wells are not immediately adjacent to the SW gaging
station. Distances between wells and SW gages range from about 20 to 100 feet distance. The
calculated differences between GW elevations and SW stages could therefore represent a
combination of horizontal and vertical gradients.
Plots of the simulated transient fluxes between SW and GW at the four target stations (128-6, 128-
7, 128-11, and 128-13) show that as the flooding event occurred, fluxes out of the river
(downwelling) increase as SW stages rise above GW elevations. This is illustrated in Figure 5.5-
13 for target 128-6 (see Appendix B for all four target stations). Downwelling fluxes are quickly
followed by conversion to upwelling fluxes as GW flows back towards the SW.
Of note is that the simulated differences between GW and SW elevation can be as little as 0.1 feet,
which is much less than the calibrated target residuals of the model. This indicates that the current
preliminary MODFLOW model will require further calibration before simulation of small vertical
gradients (both in magnitude and direction) can be made. Also, the transient river stages are
currently based on estimates of an equivalent open water stage during the spring melt flooding
event). More representative flooding stages will be obtained via output from the River1D and
River2D Ice Processes models once they are complete (SIR Study 7.6).
5.5.4. Water Table Mapping
As described in Section 4.5.4, a total of six water table maps corresponding to six different time
periods were developed for FA-128 (Slough 8A) and FA-104 (Whiskers Slough), three maps
corresponding to three time periods were developed for FA-138 (Gold Creek), and two maps
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corresponding to two periods were developed for FA-115 (Slough 6A). Specific time periods
assigned to each Focus Area are listed in Table 4.5-1.
Development of the water table maps was achieved by first assembling the respective QC3 water
level data for each of the wells and SW measurement stations within the area for the specified
dates. These data sets included both telemetered and self-logging data as well as manual
measurements as available. The Open-water Flow Routing Model (OWFRM) was also used to
estimate water levels within the centerlines of each of the Focus Areas for the respective dates
during the open-water period. These data sets were then combined and served as the basis for geo-
spatially defining elevational isopleths within each Focus Area. Specific contours were defined
by a combination of visual interpretation and interpolation. Figures 5.5-14, Figure 5.5-15, Figure
5.5-16 and Figure 5.5-17 depict water table maps for FA-104 (Whiskers Slough), FA-115 (Slough
6A), FA-128 (Slough 8A), and FA-138 (Gold Creek) respectively for one of the six periods (Late
Fall - October 9, 2013). Appendix A provides a complete description of the methods used in
developing the maps and contains the water table maps for each of the Focus Areas for the times
specified.
These water table maps will be useful for evaluating GW/SW interactions and responses under
different river stage conditions, and also for interpreting GW level changes under different project
operations. The water table maps may also be useful in the calibration and validation process of
the MODFLOW GW models.
5.5.5. Continuation of Data Collection and QC3 Data Review
As noted in SIR Study 7.5, Section 4.5, since the June 2014 ISR, AEA has continued to collect
data from many stations located within the Middle River Segment of the Susitna River and selected
locations in the Lower River Segment.
The data being collected will serve to support not only the RIFS (Study 8.6), but also a number of
other multidisciplinary resource studies including the IFS (Study 8.5), Geomorphology Study
(Study 6.5 and 6.6), Ice Processes Study (Study 7.6), and Water Quality Study (Study 5.5). A
description of the types of data being collected at each of the Focus Area stations is described in
ISR Study 7.5, Section 4.5 and displayed in ISR Study 7.5, Figures 4.5-1 through 4.5-4.
5.6. Aquatic Habitat Groundwater / Surface-Water Interactions
Groundwater activities completed in support of the IFS (Study 8.5) were described in Section 4.6
and in most cases, were the same as those described in Section 5.5 for the RIFS (Study 8.6). These
are summarized below.
5.6.1. Preparation and Submittal of Technical Memorandum – GW/SW
Relationships in Lateral Aquatic Habitats
A TM (GWS and R2 2014b) was prepared and submitted in September 2014 that described
analytical methods being applied for evaluating GW/SW interactions within lateral aquatic
habitats. The TM provided an overview of the importance of GW to fish habitat in the Susitna
River and described data collection and analysis activities designed to evaluate how Project
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operations may affect such habitats. Several examples of data analysis were presented for FA-128
(Slough 8A) that demonstrated relationships between SW stage and GW levels (Figure 5.6-1), and
SW and GW temperatures (Figure 5.6-2). The TM also discussed the dynamics of GW upwelling
and downwelling and provided examples of both as reflected by plots of streambed temperature at
depth in comparison to SW/well water levels in FA-128 (Slough 8A) (Figure 5.6-3) and FA-138
(Gold Creek) (Figure 5.6-4). The TM also defined the following three categories of lateral habitats
as influenced by differing GW processes:
Riverine Hydrology Dominated
o Flow, stage, and water quality conditions in lateral habitats are predominantly
influenced by mainstem flow, stage, and water quality conditions.
Transitional Hydrology Dominated
o Flow, stage and water quality conditions in lateral habitats vary between riverine
and upland dominated sources of flow due to seasonal and event related flow
conditions.
Upland (or Hillslope) Dominated
o Flow, stage and water quality conditions in lateral habitats are predominantly
influenced by sources of GW and SW that originate in upland areas.
As described in Section 5.4, these categories will be applied (where possible) to the GW mapping
exercise being conducted by AEA.
5.6.2. Groundwater Technical Team Meeting
A Groundwater Technical Team Meeting was conducted on December 5, 2014 as a follow-up to
the October 2014 ISR meetings and to discuss the two Technical Memoranda that were prepared
relative to the RIFS (Study 8.6) (see above) and IFS (Study 8.5) (Section 4.4.1) studies.
5.6.3. Preliminary Three-dimensional MODFLOW Model for FA-128 (Slough 8A)
As described in Section 5.5.3 above, a preliminary three dimensional MODFLOW model was
successfully developed for FA-128 (Slough 8A) and is more fully described in Appendix B. Once
fully calibrated, the MODFLOW model can be used, in conjunction with outputs provided by the
OWFRM, River1D and River 2D Ice Processes models and the 2D hydraulic models (SRH-2D),
to evaluate the effects of different Project operational scenarios on GW/SW interactions. The
output from MODFLOW can also be linked with the 2D PHABSIM Habitat Models that have
incorporated “Upwelling” as one of the HSC metrics (SIR Study 8.5, Section 5.5 and Appendix
D) for evaluating Project operational effects on spawning and incubation habitats. Specifically,
GW response functions can be developed from the MODFLOW output as analytical expressions
that can be used to quantify predicted changes in GW fluxes due to different scenarios of project
operations. Project induced changes to GW temperatures that are important for overwintering egg
incubation can also be evaluated with model output but will require additional model refinement.
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5.6.4. Water Table Mapping
As described in Section 5.5.4, AEA prepared a time series of water table maps for four Focus
Areas (FA-104 [Whiskers Slough], FA-115 [Slough 6A], FA-128 [Slough 8A], and FA-138 [Gold
Creek]), that depict GW elevations under different seasonal flow conditions (Appendix A).
5.6.5. Continuation of Data Collection and QC3 Data Review
As noted in SIR Study 7.5, Section 4.6, since the June 2014 ISR, AEA has continued to collect
data from many stations located within the Middle River Segment of the Susitna River and selected
locations in the Lower River Segment.
Results from the September 2014 field effort to collect discharge measurements within Focus
Areas are presented in Table 5.6-1, which is a duplicate of SIR Study 6.6, Table 5.1-14 from
Geomorphology Modeling (Study 6.6). Overall, a total of 52 measurements were made consisting
of seven measurements in FA-104 (Whiskers Slough), three in FA-113 (Oxbow 1), five in FA-
115 (Slough 6A), fourteen in FA-128 (Slough 8A), twelve in FA-138 (Gold Creek), one in FA-
141 (Indian River) and ten in FA-144 (Slough 21). These data will support not only the GW Study
but also a number of other multidisciplinary resource studies including the IFS (Study 8.5),
Geomorphology Study (Study 6.5 and 6.6), Ice Processes Study (Study 7.6), and Water Quality
Study (Study 5.5).
5.7. Water Quality in Selected Habitats
Activities related to this objective completed by AEA since the June 2014 ISR were described in
Section 4.7.
Overall, AEA has collected a robust set of water quality data from a number of studies (Studies
4.5, 5.5, 7.5 and 8.5) that has included data from GW wells and adjoining areas. ISR Study 7.5,
Section 5.7 provides additional detail regarding types of water quality data that have been collected
within the Focus Areas and presents several examples that illustrate how surface flows can
influence GW temperatures. Analyses have been completed to evaluate potential relationships of
microhabitat variables to fish abundance and the Baseline Water Quality Study has been
completed. Sufficient data have been collected and will be used in conjunction with Fish Habitat
Models, Water Quality Models (Study 5.6), and the MODFLOW models to more fully evaluate
how Project operations may affect both surface and GW water quality conditions. The objective
of this particular GW Study element has been met.
5.8. Winter Groundwater / Surface-Water Interactions
As noted in Section 4.8 above, data collected as part of the coordinated 2014 winter studies were
evaluated and presented and discussed as part of the September TM pertaining to GW/SW
relationships in lateral habitats (GWS and R2 2014b) Those data consisted of winter discharge
measurements collected during three time periods within three Focus Areas. Those data were
summarized and presented as Table 3.1-2 in the TM; raw data were provided in Appendix B of the
TM. In part, the discharge measurements provided estimates of GW inflow occurring between
upper and lower measurement points. AEA has continued to collect data during the winter period
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from a number of the GW well stations and remote cameras. Those data will be used not only for
evaluating GW/SW interactions but also by the Ice Processes Study (Study 7.6) for calibration of
the River2D models within Focus Areas.
5.9. Shallow Groundwater Users
Four homeowner wells were instrumented with continuously recording pressure transducers in
2013 and have provided data up through September 2015. Data from these wells will be used in
combination with SW data collected on the mainstem Susitna River, as well as output from the
OWFRM and River1D hydrology models to evaluate potential Project operational effects on
shallow GW wells within the Middle River Segment.
6. DISCUSSION
6.1. Existing Data Synthesis
Since the June 2014 ISR, AEA has completed the review of literature and prepared a document
that summarizes the information (Appendix C). The document included the review of 12 reports
and documents completed as part of the 1980s studies, as well as a review of more contemporary
literature pertaining to GW/SW relationships as evaluated for hydroelectric projects in cold
regions. The objective of this particular component of the GW Study has been met.
6.2. Geohydrologic Process-Domains
There has been no substantive activity completed on this study component since the June 2014
ISR. However,a substantial amount of data have been collected from field studies, observations,
and information gathered as part of the literature review as well as from other studies from which
to develop a conceptual understanding of the regional GW processes. The next step is to define
the GW regional scale relationship to local flow systems in the Middle River and Lower River
segments and the relationship with the process-domain river segments. Additional analysis will
be needed to determine those processes at the Focus Area scale, which will provide an indication
of how those processes are functioning within the entire Middle River Segment.
6.3. Watana Dam/Reservoir
There has been no substantive GW related activity on this element since completion of the June
2014 ISR. However, AEA has continued Project Engineering Feasibility Studies Geotechnical
Investigations, and the Geology and Soils Characterization Study (Study 4.5) (see SIR Study 4.5
for description of work) and these efforts are meeting study objectives set forth in the FERC -
approved Study Plan.
6.4. Upwelling / Springs Broad-Scale Mapping
The primary activity on this element has been associated with the differentiation of upwelling areas
within FA-128 (Slough 8A) AEA is applying the same general process for identifying GW areas
throughout the entire Middle River Segment of the Susitna River.
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6.5. Riparian Vegetation Dependency on Groundwater / Surface-
Water Interactions
Since the June 2014 ISR, AEA completed a number of GW activities (described in Sections 4.5
and 5.5) related to this objective. One of the key elements needed to meet the objective is
development of GW models that can be used to assess Project operational effects on GW/SW
interactions and how those may translate into effect on the riparian community. As noted in
Section 5.5, a preliminary three-dimensional MODFLOW GW model has been developed for FA-
128 (Slough 8A) (Appendix B). This model, once fully calibrated will be used for making that
assessment at FA-128. Additional MODFLOW models can be developed for FA-104 (Whiskers
Slough), FA-115 (Slough 6A), and FA-138 (Gold Creek) and can likewise be used for evaluating
Project effects on GW/SW interactions in those areas. The time series of water table maps that
have been developed and presented in Appendix A provide useful information regarding pre-
project GW/SW interactions and how these change due to stage changes.
The combination of data and analysis collected and completed in 2013 up through June 2014,
coupled with additional data and analysis completed in 2014 and 2015 has provided a solid
framework of information and allowed the development of modeling tools from which to evaluate
Project operational effects on GW/SW interactions and resulting effects on riparian vegetation.
However, the modeling tools will require further development and refinement before they can be
reliably used for evaluating overall project effects. Overall, the activities that have been completed
to date are consistent with those specified in the FERC-approved Study Plan.
6.6. Aquatic Habitat Groundwater / Surface-Water Interactions
Activities related to this study component largely mirror those of the RIFS component described
above (Section 6.5), except that a separate TM was prepared that described the preliminary
analysis of GW/SW interactions supportive of the IFS (Study 8.5). Specific activities were
described in SIR Study 7.5, Section 5.5. Like the RIFS GW/SW analysis described above, one of
the key elements needed to meet this study objective is development of GW models that can be
used to assess Project operational effects on GW/SW interactions and how those may translate into
effects on important fish and aquatic habitats that are being evaluated as part of the IFS (Study
8.5). The MODFLOW model developed for FA-128 (Appendix B), once fully calibrated will be
used for making that assessment at FA-128. Additional MODFLOW models can be developed for
FA-104 (Whiskers Slough), FA-115 (Slough 6A), and FA-138 (Gold Creek) and can likewise be
used for evaluating Project effects on GW/SW interactions and resulting effects on fish and aquatic
habitats in those areas. Overall, the activities that have been completed to date are consistent with
those specified in the FERC-approved Study Plan.
6.7. Water Quality in Selected Habitats
AEA has collected sufficient water quality data related to GW/SW interactions that can be used in
conjunction with Fish Habitat models (Study 8.5), Water Quality models (Study 5.6), and the
MODFLOW GW models to evaluate how Project operations may affect both surface and GW
water quality conditions that comprise important fish and aquatic habitat. The objective of this
particular GW Study element has been met.
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6.8. Winter Groundwater / Surface-Water Interactions
Data collected as part of the coordinated 2014 winter studies were evaluated and presented and
discussed as part of the September TM pertaining to GW/SW relationships in lateral habitats
(GWS and R2 2014b) AEA has continued to collect data during the winter period from a number
of the GW well stations and remote cameras. Overall, the activities that have been completed to
date are consistent with those specified in the FERC-approved Study Plan.
6.9. Shallow Groundwater Users
Overall, the activities that have been completed to date are consistent with those specified in the
FERC-approved Study Plan.
7. CONCLUSION
Data collection during the 2013 field effort provided a robust set of data contributory to meeting
each of the study objectives. As described in ISR Study 7.5 and in SIR Study 7.5, Sections 4
through 6 above, data collection and analysis activities have continued throughout 2014 and into
2015 and have resulted in meeting several of the study objectives, as well as advancing the work
progress on the others. Importantly, data collection will continue at selected stations to provide
additional GW related data that can be used by other resource studies including the IFS (Study
8.5), RIFS (Study 8.6), Ice Processes (Study 7.6) and other studies requiring empirical surface and
GW data and observations. Based on data collection completed in 2013, preliminary analyses, and
plans for continued data collection, AEA expects to achieve the objectives of this study.
Conclusions regarding the status of each of the nine objectives in the GW Study (Study 7.5) are
presented below.
7.1. Existing Data Synthesis
AEA has completed the review of literature and prepared a document th at summarizes the
information (Appendix C). The objective of this particular component of the GW Study has been
met.
7.2. Geohydrologic Process-Domains
Completion of geohydrologic process-domains will utilize existing data and information that have
been collected and compiled in the GW Study and as part of the RIFS (Study 8.6) and
Geomorphology (Study 6.5 and 6.6) studies.
Additional analysis will be completed to define the GW regional scale relationship to local flow
systems in the Middle River and Lower River segments. This will be completed by first evaluating
GW vertical gradient response functions resulting from precipitation, flow and ice processes at the
Focus Area scale. This understanding can then be expanded to other sections of the Middle River
Segment.
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7.3. Watana Dam/Reservoir
AEA has continued Project Engineering Feasibility Studies, Geotechnical Investigations, and the
Geology and Soils Characterization Study (Study 4.5) (see SIR Study 4.5 for description of work)
and these efforts are meeting the study objectives set forth in the FERC-approved Study Plan.
7.4. Upwelling/Springs Broad-Scale Mapping
The upwelling/springs broad-scale mapping study component is ongoing.
7.5. Riparian Vegetation Dependency on Groundwater / Surface-
Water Interactions
Substantial data have been and are continuing to be collected and analyzed consistent with the
FERC Approved Study Plan. A preliminary three-dimensional MODFLOW GW model has been
developed for FA-128 (Slough 8A). The model will require further calibration and refinement and
will then be used for evaluating Project operational effects as defined by the OWFRM, SRH-2D
hydraulic model, and the River1D and River2D Ice Processes models, on GW/SW interactions
within that Focus Area. The model outputs can be linked with the RIFS riparian models (SIR
Study 8.6, Section 6.6) for evaluating how the resulting GW/SW interactions will influence
riparian floodplain vegetation. Additional MODFLOW models can be developed for FA-104
(Whiskers Slough), FA-115 (Slough 6A), and FA-138 (Gold Creek) and can likewise be used for
evaluating Project effects on GW/SW interactions in those areas.
Additional analysis of well data collected within Riparian transects in the Lower River Segment
(SIR Study 8.6) will provide an understanding of how Project operational changes may influence
riparian vegetation.
7.6. Aquatic Habitat Groundwater / Surface-Water Interactions
Substantial data have been and are continuing to be collected and analyzed consistent with the
FERC Approved Study Plan.
A preliminary three-dimensional MODFLOW GW model has been developed for FA-128 (Slough
8A). The model will require further calibration and refinement and will then be used for evaluating
Project operational effects as defined by the OWFRM, SRH-2D hydraulic model, and the River1D
and River2D Ice Processes models, on GW/SW interactions within that Focus Area. The model
outputs can be linked with the 2D Fish Habitat (PHABSIM) models (SIR Study 8.5) for evaluating
how the resulting GW/SW interactions will influence fish and aquatic habitats. Additional
MODFLOW models can be developed for FA-104 (Whiskers Slough) FA-115 (Slough 6A), and
FA-138 (Gold Creek) and can likewise be used for evaluating Project effects on GW/SW
interactions and effects on fish habitat in those areas.
7.7. Water Quality in Selected Habitats
AEA has collected sufficient water quality data related to GW/SW interactions that can be used in
conjunction with 2D Fish Habitat (PHABSIM) Models, Water Quality Models (Study 5.6), and
the MODFLOW GW models to evaluate how Project operations may affect both surface and GW
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water quality conditions that comprise important fish and aquatic habitat. The specific objective
of characterizing water quality characteristics in selected habitats has been met.
7.8. Winter Groundwater / Surface-Water Interactions
AEA will continue to collect data at selected GW well stations throughout the winter period. These
data along with GW and SW data collected during the winters of 2012/2013, and 2013/2014 will
provide a substantial database of information from which to evaluate winter GW/SW interactions.
The development of calibrated MODFLOW GW models in FA-104 (Whiskers Slough), FA-115
(Slough 6A), FA-128 (Slough 8A), and FA-138 (Gold Creek) will be used for evaluating effects
of Project operations on GW/SW interactions (including upwelling and downwelling) during the
winter period. These models will use outputs from the OWFRM (SIR Study 8.5, Appendix B) and
the River1D and River2D Ice Processes models (SIR Study 7.6) to provide stage data based on
bathymetric maps of each of the Focus Areas. This modeling will be linked with the 2D Fish
Habitat models for evaluating Project operational effects on GW/SW interactions and effects on
overwintering egg incubation and embryo survival.
7.9. Shallow Groundwater Users
Data collected from the homeowner wells can be used in combination with SW data collected on
the mainstem Susitna River, as well as output from the OWFRM and River1D hydrology models
to evaluate potential Project operational effects on shallow GW wells within the Middle River
Segment.
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8. LITERATURE CITED
Alaska Energy Authority (AEA). 2012. Revised Study Plan. Susitna-Watana Hydroelectric
Project, FERC Project No. 14241 Submittal: December 14, 2012. http://www.susitna-
watanahydro.org/study-plan.
Alaska Energy Authority (AEA). 2014. Initial Study Report. Susitna-Watana Hydroelectric
Project, FERC Project No. 14241 Submittal: June 3, 2014. http://www.susitna-
watanahydro.org/type/documents/.
American Society for Testing and Materials (ASTM). 2008. D5981 - 96(2008) Standard Guide
for Calibrating a Groundwater Flow Model Application, ASTM, 19 pp.
American Society for Testing and Materials (ASTM). 2010. D6170 - 97(2010) Standard Guide
for Selecting a Groundwater Modeling Code, ASTM, 19 pp.
Federal Energy Regulatory Commission (FERC). 2013. Study Plan Determination on 14
remaining studies for the Susitna-Watana Hydroelectric Project. Susitna-Watana
Hydroelectric Project, FERC No. P-14241. April 1, 2013.
http://elibrary.FERC.gov/idmws/file_list.asp?accession_num=20130401-3022.
Geo-Watersheds Scientific (GWS) and R2 Resource Consultants (R2). 2014a. Groundwater and
Surface-Water Relationships in Support of Riparian Vegetation Modeling. Susitna-
Watana Hydroelectric Project, FERC No. P-14241 Submittal: September 30, 2014,
Attachment D, Study 7.5 Technical Memorandum. Prepared for Alaska Energy Authority,
Anchorage, Alaska. http://www.susitna-watanahydro.org/wp-
content/uploads/2014/09/07.5_GW_GWS_T5_TM_Riparian_Final_Draft_20140926.pdf.
Geo-Watersheds Scientific (GWS) and R2 Resource Consultants (R2). 2014b. Preliminary
Groundwater and Surface-Water Relationships in Lateral Aquatic Habitats within Focus
Areas FA-128 (Slough 8A) and FA-138 (Gold Creek) in the Middle Susitna River. Susitna-
Watana Hydroelectric Project, FERC No. P-14241 Submittal: September 30, 2014,
Attachment C, Study 7.5 Technical Memorandum. Prepared for Alaska Energy Authority,
Anchorage, Alaska. http://www.susitna-watanahydro.org/wp-
content/uploads/2014/09/07.5_GW_GWS_T6_TM_Aquatic_Hydro_Final_Draft_201409
25.pdf.
Geo-Watershed Scientific (GWS). 2015. December 5, 2014 Technical Team Meeting Notes and
Presentation. Susitna-Watana Hydroelectric Project, FERC No. P-14241 Submittal:
November 2015, 2014-2015 Study Implementation Report, Study 7.5, Appendix D.
Prepared for Alaska Energy Authority, Anchorage, Alaska.
Harza-Ebasco Susitna Joint Venture (HESJV). 1984. Susitna Hydroelectric Project Slough
Geohydrology Studies. Prepared in cooperation with R&M Consultants, Inc. for the
Alaska Power Authority April. APA Document No. 1718.
Pacific Groundwater Group (PGG). 2015a. Preliminary Water Table Contour Maps for Focus
Areas FA-104, FA-115, FA-128, and FA-138. Susitna-Watana Hydroelectric Project,
FERC No. P-14241 Submittal: November 2015, 2014- 2015 Study Implementation Report,
Study 7.5, Appendix A. Prepared for Alaska Energy Authority, Anchorage, Alaska.
2014-2015 STUDY IMPLEMENTATION REPORT GROUNDWATER STUDY (STUDY 7.5)
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 28 November 2015
Pacific Groundwater Group (PGG). 2015b. Preliminary MODFLOW Three Dimensional
Groundwater Model for Focus Area FA-128 (Slough 8A). Susitna-Watana Hydroelectric
Project, FERC No. P-14241 Submittal: November 2015, 2014-2015 Study Implementation
Report, Study 7.5, Appendix B. Prepared for Alaska Energy Authority, Anchorage,
Alaska.
Pacific Groundwater Group (PGG). 2015c. Summary Review of Susitna River Hydrogeologic
Studies Conducted in the 1980s and other Non-Project Related Studies with Relevance to
Proposed Susitna-Watana Dam Project. Susitna-Watana Hydroelectric Project, FERC No.
P-14241 Submittal: November 2015, 2014-2015 Study Implementation Report, Study 7.5,
Appendix C. Prepared for Alaska Energy Authority, Anchorage, Alaska.
R & M Consultants, Inc. and Woodward-Clyde Consultants. 1985. Instream Flow Relationships
Report Series Physical Processes of the Middle Susitna River Technical Report No. 2.
Prepared under contract with Harza-Ebasco Susitna Joint Venture for the Alaska Power
Authority. APA Document No. 2828. Available at:
http://www.arlis.org/docs/vol1/Susitna/28/APA2828.pdf
R2 Resource Consultants, Inc. (R2). 2014a. Middle River Fish Habitat and Riverine Modeling
Proof of Concept. Susitna-Watana Hydroelectric Project, FERC No. P-14241 Submittal:
June 3, 2014, Initial Study Report, Study 8.5, Part C, Appendix N. Prepared for Alaska
Energy Authority, Anchorage, Alaska. http://www.susitna-watanahydro.org/wp-
content/uploads/2014/06/08.5_IFS_ISR_PartC_2_of_2.pdf.
R2 Resource Consultants (R2). 2014b. Evaluation of Relationships between Fish Abundance and
Specific Microhabitat Variables. Susitna-Watana Hydroelectric Project, FERC No. P-
14241 Submittal: September 17, 2014, Attachment G, Study 8.5 Technical Memorandum.
Prepared for Alaska Energy Authority, Anchorage, Alaska. http://www.susitna-
watanahydro.org/wp-content/uploads/2014/09/08.5_IFS_R2_TM_FishAbundance-
MicrohabitatVariables_FINAL.pdf.
R2 Resource Consultants, Inc. (R2). 2014c. 2012-2013 Instream Flow Winter Pilot
Studies. Susitna-Watana Hydroelectric Project, FERC No. P-14241 Submittal: June 3,
2014, Initial Study Report, Study 8.5, Part C, Appendix L. Prepared for Alaska Energy
Authority, Anchorage, Alaska. http://www.susitna-watanahydro.org/wp-
content/uploads/2014/06/08.5_IFS_ISR_PartC_2_of_2.pdf.
R2 Resource Consultants, Inc. (R2). 2014d. 2013-2014 Instream Flow Winter Studies. Susitna-
Watana Hydroelectric Project, FERC No. P-14241 Submittal: September 17, 2014,
Attachment H, Study 8.5 Technical Memorandum. Prepared for Alaska Energy Authority,
Anchorage, Alaska. http://www.susitna-watanahydro.org/wp-
content/uploads/2014/09/08.5_IFS_R2_TM_2013-2014WinterStudies.pdf.
2014-2015 STUDY IMPLEMENTATION REPORT GROUNDWATER STUDY (STUDY 7.5)
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R2 Resource Consultants (R2) and LGL Alaska Research Associates (LGL). 2014a. Winter
Sampling Report (2012-2013). Susitna-Watana Hydroelectric Project, FERC No. P-14241
Submittal: June 3, 2014, Initial Study Report, Study 9.6, Part A, Appendix C. Prepared for
Alaska Energy Authority, Anchorage, Alaska. http://www.susitna-watanahydro.org/wp-
content/uploads/2014/05/09.06_FDAML_ISR_PartA_4_of_5_App_C.pdf.
R2 Resource Consultants (R2) and LGL Alaska Research Associates (LGL). 2014b. 2013-2014
Winter Fish Study. Susitna-Watana Hydroelectric Project, FERC No. P-14241 Submittal:
September 17, 2014, Attachment D, Study 9.6 Technical Memorandum. Prepared for
Alaska Energy Authority, Anchorage, Alaska. http://www.susitna-watanahydro.org/wp-
content/uploads/2014/09/09.06_FDAML_Winter_TM.pdf.
Tetra Tech. 2014. TIR Images, Study 5.5. Susitna-Watana Hydroelectric Project, FERC No. P-
14241 Submittal: June 3, 2014, Initial Study Report, Study 5.5, Part A, Appendix
J. Prepared for Alaska Energy Authority, Anchorage, Alaska. http://www.susitna-
watanahydro.org/wp-content/uploads/2014/05/05.5_WQ_ISR_PartA_6_of_6_App_J.pdf.
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9. TABLES
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Table 4.5-1. Focus Areas and respective target dates for development of Water-Level Contour Maps for the
Susitna River.
Focus Area
9/13/2013
Fall
10/9/2013
Late Fall
2/20/2014
Ice Cover / Ice Jam
4/20/2014
Pre-breakup
7/11/2014
Post-breakup
8/13/2014
Summer
FA-104 (Whiskers Slough) X X X X X X
FA-115 (Slough 6A) X X
FA-128 (Slough 8A) X X X X X X
FA-138 (Gold Creek) X X X
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Table 4.5-2. Groundwater Study data collection stations in the Lower River, FA-104 (Whiskers Creek), PRM 112, FA-113 (Oxbow 1), FA-115 (Slough
6A), FA-128 (Slough 8A), FA-138 (Gold Creek), FA-141 (Indian River), FA-144 (Slough 21), and the ESS Stations. (Updated ISR Study 7.5 Tables 4.5-1
to 4.5-4.)
The data collection parameters include the following: air temperature, AT; camera images, Cam; groundwater level, GWL; groundwater temperature, GWT;
groundwater conductivity GWC; net radiation, NR, relative humidity, RH; sap flow, SF; soil heat flux, SHF; soil-moisture profile, SMP; soil-temperature profile,
SoTP; streambed temperature profile, STP; summer precipitation, SP; solar radiation, SR; surface-water conductivity, SWC, surface-water height, GH; surface-
water temperature, WT; wind direction, WD; wind speed, WS. A (#) indicates more than one measurement location.
Location
Station Short
Names
Station
Primary
Purpose Latitude Longitude Data Collection Parameters Status
Lower River ESGLR1-1 Groundwater 62.2517 -150.14339 WT, CAM Removed 1,2
Lower River ESGLR2-1 Groundwater 61.950062 -150.11470 WT, CAM Removed 1,2,6
Lower River ESGLR3-1 Groundwater 61.778998 -150.19232 WT, CAM Removed 1,2
Lower River ESGLR4-1 Groundwater 61.621293 -150.36835 WT, CAM Removed 1,2
Lower River ESGLR4-2 Groundwater 61.621845 -150.35375 WT, CAM Removed 1,2
PRM 112 ESSPRM112-1 Surface Water 62.47246 -150.11835 GH Removed 1
PRM 112 ESSPRM112-2 Surface Water 62.4706 -150.11489 GH Removed 1
PRM 112 ESSPRM112-3 Surface Water 62.46608 -150.11682 GH Removed 1
FA-104 ESSFA104-1 Surface Water 62.37676 -150.16934 AT, GH, WT, STP, Cam Maintained
FA-104 ESMFA104-2 Meteorological 62.37863 -150.1719 AT, RH, SMP, SR, SoTP, SHF, GWL, GWT, WD, WS, NR Maintained 5
FA-104 ESGFA104-3 Groundwater 62.37934 -150.17373 GWL, GWT Maintained
FA-104 ESGFA104-4 Groundwater 62.37908 -150.17363 GWL, GWT, SF Removed 7
FA-104 ESGFA104-5 Groundwater 62.3781 -150.17029 GH(2), WT(2), GWL, GWT Maintained 8
FA-104 ESGFA104-6 Groundwater 62.378 -150.16912 GWL(2), GWT(2), SF Maintained 9
FA-104 ESGFA104-7 Groundwater 62.37764 -150.16822 GWL, GWT, SF Maintained 9
FA-104 ESGFA104-8 Groundwater 62.37692 -150.16562 GWL, GWT, SF, GH, WT Maintained 9
FA-104 ESGFA104-9 Groundwater 62.37626 -150.17091 GWL(2), GWT(2), STP, SWC, other Maintained 7
FA-104 ESGFA104-10 Groundwater 62.38402 -150.15125 GWL(1), GWT(1), GH, WT, STP(1) Maintained 8
FA-104 ESGFA104-11 Groundwater 62.37622 -150.16996 GWL, GWT Maintained
FA-104 ESGFA104-12 Groundwater 62.37622 -150.16996 GWL, GWT Maintained
FA-104 ESGFA104-13 Groundwater 62.37824 -150.171 GWL, GWT Maintained
FA-104 ESCFA104-16 Camera 62.37457 -150.1685 Cam Removed 1,4
FA-104 ESCFA104-17 Camera 62.37676 -150.17157 Cam Removed 1,4
FA-104 ESCFA104-18 Camera 62.37943 -150.16961 Cam Removed 1
FA-104 ESCFA104-19 Camera 62.37986 -150.16679 Cam Removed 1
FA-104 ESCFA104-20 Camera 62.38351 -150.15477 Cam Removed 1
FA-104 ESCFA104-21 Camera 62.38388 -150.15211 Cam Removed 1
FA-104 ESCFA104-22 Camera 62.3818 -150.16376 Cam Removed 1
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Location
Station Short
Names
Station
Primary
Purpose Latitude Longitude Data Collection Parameters Status
FA-104 ESSFA104-23 Surface Water 62.38629 -150.15412 GH Removed 1
FA-104 ESSFA104-24 Surface Water 62.37968 -150.16311 GH Removed 1
FA-113 ESGFA113-1 Groundwater 62.489471 -150.10515 GWL(2), GWT(2), STP, GH(2), WT(2), WSE, Q Removed 1,2
FA-113 ESCFA113-2 Camera 62.492532 -150.10396 Cam Removed 1
FA-113 ESCFA113-3 Camera 62.48663 -150.09798 Cam Removed 1
FA-113 ESCFA113-4 Camera 62.488959 -150.10530 Cam Removed 1
FA-113 ESSFA113-5 Surface Water 62.49647 -150.11095 GH Removed 1
FA-113 ESSFA113-6 Surface Water 62.49245 -150.11003 GH Removed 1
FA-113 ESSFA113-7 Surface Water 62.48765 -150.10101 GH Removed 1
FA-115 ESMFA115-1 Meteorological 62.51892 -150.12688 AT, RH, SMP, SR, SoTP, SHF, GWL(2), GWT(2), WD, WS, NR Maintained
FA-115 ESGFA115-2 Groundwater 62.51929 -150.13084 GWL, GWT, GH, WT Maintained
FA-115 ESGFA115-3 Groundwater 62.51905 -150.1255 GWL, GWT, GH, WT Maintained
FA-115 ESGFA115-4 Groundwater 62.51906 -150.1247 GWL, GWT Maintained
FA-115 ESGFA115-5 Groundwater 62.51876 -150.12258 GWL, GWT, GH, WT Maintained
FA-115 ESGFA115-6 Groundwater 62.51868 -150.12135 GWL, GWT Maintained
FA-115 ESGFA115-7 Groundwater 62.51863 -150.12064 GWL, GWT, GH, WT Maintained 7
FA-115 ESGFA115-8 Groundwater 62.51914 -150.12948 GWL, GWT Removed 1,2
FA-115 ESCFA115-11 Camera 62.51933 -150.13072 Cam Removed 1
FA-115 ESCFA115-12 Camera 62.51896 -150.12046 Cam Removed 1
FA-115 ESCFA115-13 Camera 62.51507 -150.12476 Cam Removed 1,4
FA-115 ESCFA115-14 Camera 62.51357 -150.12182 Cam Removed 1
FA-115 ESSFA115-15 Surface Water 62.51542 -150.12418 GH Removed 1
FA-115 ESSFA115-16 Surface Water 62.51407 -150.12243 GH Removed 1,4
FA-115 ESSFA115-17 Surface Water 62.51747 -150.12516 GH Removed 1
FA-115 ESSFA115-18 Surface Water 62.51809 -150.12337 GH Removed 1
FA-115 ESSFA115-19 Surface Water 62.51696 -150.12987 GH Removed 1
FA-115 ESSFA115-20 Surface Water 62.51675 -150.12465 GH Removed 1
FA-128 ESSFA128-1 Surface Water 62.66384 -149.90494 AT, GH, WT, STP, Cam Maintained
FA-128 ESGFA128-2 Groundwater 62.67204 -149.89403 GWL, GWT, GH, WT Maintained 7
FA-128 ESGFA128-3 Groundwater 62.67179 -149.8939 GWL, GWT, SF Maintained 9
FA-128 ESGFA128-4 Groundwater 62.67049 -149.89341 GWL, GWT Maintained
FA-128 ESGFA128-5 Groundwater 62.66765 -149.89352 GWL, GWT, GH, WT, SF Maintained 7,9
FA-128 ESGFA128-6 Groundwater 62.6666 -149.8932 GWL, GWT, GH, WT Maintained
FA-128 ESGFA128-7 Groundwater 62.6655 -149.89707 GWL(2), GWT(2), GWC, GH, WT, SWC, STP Removed 1,4,2
FA-128 ESMFA128-8 Meteorological 62.67052 -149.89485 AT, RH, SMP, SR, SoTP, SHF, WD, WS, NR Maintained
FA-128 ESGFA128-9 Groundwater 62.66349 149.90730 GWL(2), GWT(2), SF Maintained 9
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Location
Station Short
Names
Station
Primary
Purpose Latitude Longitude Data Collection Parameters Status
FA-128 ESGFA128-10 Groundwater 62.66393 -149.90766 GWL, GWT, SF Maintained
FA-128 ESGFA128-11 Groundwater 62.66596 -149.91077 GWL, GWT, GH, WT Maintained
FA-128 ESGFA128-12 Groundwater 62.66711 -149.91272 GWL, GWT, GH, WT Maintained
FA-128 ESGFA128-13 Groundwater 62.68626 -149.90953 GWL(2), GWT(2), GWC, GH, WT, SWC, STP Maintained
FA-128 ESSFA128-14 Surface Water 62.67271 -149.89112 GH, WT Maintained
FA-128 ESSFA128-16 Surface Water 62.67015 -149.88548 GH, WT Removed 1
FA-128 ESSFA128-17 Surface Water 62.66888 -149.88489 GH, WT Removed 1
FA-128 ESGFA128-18 Groundwater 62.66538 -149.89694 GWL, GWT Maintained
FA-128 ESGFA128-19 Groundwater 62.66525 -149.89681 GWL, GWT Maintained
FA-128 ESGFA128-20 Groundwater 62.663048 -149.90938 GWL, GWT Maintained
FA-128 ESGFA128-21 Groundwater 62.66485 -149.90892 GWL, GWT Maintained
FA-128 ESGFA128-22 Groundwater 62.66088 -149.91993 GH, WT Removed 1,4
FA-128 ESGFA128-23 Groundwater 62.66466 -149.91168 GWL, GWT Removed 1,4
FA-128 ESGFA128-24 Groundwater 62.66534 -149.90681 GWL, GWT Maintained
FA-128 ESGFA128-25 Groundwater 62.66767 -149.90671 GWL, GWT Maintained
FA-128 ESGFA128-26 Groundwater 62.66946 -149.89789 GWL, GWT Removed 2,4
FA-128 ESGFA128-27 Groundwater 62.67092 -149.88946 GWL, GWT Maintained 8
FA-128 ESFFA128-28 Support 62.66442 -149.90244 PIT tag array support Removed 1
FA-128 ESCFA128-29 Camera 62.67251 -149.88567 Cam Maintained
FA-128 ESCFA128-32 Camera 62.66754 -149.89376 Cam Maintained
FA-128 ESCFA128-33 Camera 62.67179 -149.89376 Cam Removed 1,4
FA-128 ESCFA128-34 Camera 62.66719 -149.91216 Cam Maintained
FA-128 ESCFA128-35 Camera 62.66307 -149.91039 Cam Maintained
FA-128 ESCFA128-36 Camera 62.66167 -149.91676 Cam Maintained
FA-128 ESSFA128-37 Surface Water 62.66764 -149.89849 GH Not Serviced in 20153
FA-128 ESSFA128-38 Surface Water 62.668 -149.88803 GH Removed 1,4
FA-128 ESSFA128-39 Surface Water 62.66296 -149.92723 GH Removed 1
FA-128 ESSFA128-40 Surface Water 62.66459 -149.92271 GH Removed 1
FA-138 ESGFA138-1 Groundwater 62.75758 -149.70694 AT, GWL(2), GWT(2), GH, WT, STP, SWC, SP Maintained
FA-138 ESGFA138-2 Groundwater 62.76464 -149.70595 GWL(2), GWT(2), GH, WT, STP, SWC Maintained
FA-138 ESGFA138-3 Groundwater 62.75675 -149.70559 GWL, GWT Maintained
FA-138 ESGFA138-4 Groundwater 62.76513 -149.70604 GWL, GWT Maintained
FA-138 ESGFA138-5 Groundwater 62.76555 -149.70621 GWL, GWT Maintained
FA-138 ESCFA138-8 Camera 62.75268 -149.70792 Cam Removed 1
FA-138 ESCFA138-9 Camera 62.75686 -149.70529 Cam Removed 1
FA-138 ESCFA138-10 Camera 62.76477 -149.70522 Cam Removed 1
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Location
Station Short
Names
Station
Primary
Purpose Latitude Longitude Data Collection Parameters Status
FA-138 ESCFA138-11 Camera 62.7677 -149.70755 Cam Removed 1
FA-138 ESSFA138-12 Surface Water 62.76654 -149.71311 GH Removed 1
FA-138 ESSFA138-13 Surface Water 62.76584 -149.71349 GH Removed 1
FA-138 ESSFA138-14 Surface Water 62.76679 -149.71101 GH Removed 1
FA-138 ESSFA138-15 Surface Water 62.7624 -149.70091 GH Removed 1
FA-138 ESSFA138-16 Surface Water 62.75414 -149.70740 GH Removed 1
FA-138 ESSFA138-17 Surface Water 62.76037 -149.69924 GH Removed 1
FA-141 ESSFA141-1 Surface Water 62.78811 -149.64994 GH Removed 1
FA-141 ESSFA141-2 Surface Water 62.78992 -149.64351 GH Removed 1
FA-141 ESSFA141-3 Surface Water 62.78138 -149.69122 GH Removed 1
FA-141 ESSFA141-4 Surface Water 62.78028 -149.68922 GH Removed 1
FA-141 ESSFA141-5 Surface Water 62.77979 -149.68848 GH Removed 1
FA-144 ESSFA144-1 Surface Water 62.81369 -149.57595 GH Removed 1
FA-144 ESSFA144-2 Surface Water 62.81477 -149.57385 GH Removed 1
FA-144 ESSFA144-3 Surface Water 62.81541 -149.57478 GH Removed 1
FA-144 ESSFA144-4 Surface Water 62.80695 -149.59156 GH Removed 1
PRM 17.4 ESS10 Surface Water 61.40541 -150.46021 AT, CAM, WT, GH Removed 1
PRM 24.7 ESS15 Surface Water 61.48954 -150.56207 AT, CAM, WT, GH Removed 1
PRM 29.9 ESS20 Surface Water 61.54425 -150.51533 AT, CAM Maintained
PRM 98.4 ESS30 Surface Water 62.29455 -150.11599 AT, CAM, WT, GH Removed 1
PRM 107.2 ESS40 Surface Water 62.39915 -150.13722 AT, CAM, WT, GH Maintained
PRM 116.6 ESS45 Surface Water 62.52558 -150.11487 AT, CAM, WT, GH Maintained
PRM 124.1 ESS50 Surface Water 62.61718 -150.01509 AT, CAM, WT, GH Removed 1,6
PRM 152.2 ESS55 Surface Water 62.83052 -149.38391 AT, CAM, WT, GH Maintained
PRM 176.5 ESS65 Surface Water 62.76461 -148.77414 AT, CAM, WT, GH Removed 1
PRM 187.1 ESS70 Surface Water 62.82299 -148.53834 AT, CAM, WT, GH Maintained
PRM 225 ESS80 Surface Water 62.69777 -147.54729 AT, CAM, WT, GH Maintained
Notes:
1 Station removed but survey control left in place.
2 Station removed but well left in place.
3 Station not serviced due to bear activity.
4 Station was damaged/removed.
5 Radiation sensor removed due to damage (NR no longer collected).
6 Station removed but antennae left in place.
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7 Surface-water Pressure Transducer and temperature profile string were removed due to damage (GW and WT no longer collected).
8 Well was damaged/removed (GWL and GWT no longer collected).
9 Sap flow sensors removed (SF no longer collected).
10 Station not serviced because owner-permission not received.
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Table 4.5-3. Summary of the QC3 data files used in support of this SIR and its appendices that have been delivered to GINA and are publically available
(http://gis.suhydro.org/SIR/07-Hydrology/7.5-Groundwater/).
Component1 Data File Name Description
Appendix A SIR_7_5_GW_WaterTableMapData_20151104.xlsx Elevation data for Focus Area water table maps
Appendix B SIR_7_5_GW_FA-GWSW_Network_WaterLevel_ESGFA128-21_20151104.xlsx Station ESGFA128-21 groundwater well fifteen-minute sample water levels
Appendix B SIR_7_5_GW_FA-GWSW_Network_WaterLevel_ESGFA138-4_20151104.xlsx Station ESGFA138-4 groundwater well fifteen-minute sample water levels
Appendix B SIR_7_5_GW_FA-GWSW_Network_WaterLevel_ESGFA138-5_20151104.xlsx Station ESGFA138-5 groundwater well fifteen-minute sample water levels
Appendix B SIR_7_5_GW_GW_WaterLevel_ESGFA128-11_20151104.xlsx
Station ESGFA128-11 groundwater well and side channel fifteen-minute
sample, average, maximum, and minimum water levels
Appendix B SIR_7_5_GW_GW_WaterLevel_ESGFA128-13_20151104.xlsx
Station ESGFA128-13 groundwater well and slough fifteen-minute sample,
average, maximum, and minimum water levels
Appendix B SIR_7_5_GW_GW_WaterLevel_ESGFA128-18_20151104.xlsx Station ESGFA128-18 groundwater well fifteen-minute sample water levels
Appendix B SIR_7_5_GW_GW_WaterLevel_ESGFA128-19_20151104.xlsx Station ESGFA128-19 groundwater well fifteen-minute sample water levels
Appendix B SIR_7_5_GW_GW_WaterLevel_ESGFA128-2_20151104.xlsx
Station ESGFA128-2 groundwater well and water surface fifteen-minute
sample and average water levels
Appendix B SIR_7_5_GW_GW_WaterLevel_ESGFA128-23_20151104.xlsx Station ESGFA128-23 groundwater well fifteen-minute sample water levels
Appendix B SIR_7_5_GW_GW_WaterLevel_ESGFA128-24_20151104.xlsx Station ESGFA128-24 groundwater well fifteen-minute sample water levels
Appendix B SIR_7_5_GW_GW_WaterLevel_ESGFA128-25_20151104.xlsx Station ESGFA128-25 groundwater well fifteen-minute sample water levels
Appendix B SIR_7_5_GW_GW_WaterLevel_ESGFA128-26_20151104.xlsx Station ESGFA128-26 groundwater well fifteen-minute sample water levels
Appendix B SIR_7_5_GW_GW_WaterLevel_ESGFA128-27_20151104.xlsx Station ESGFA128-27 groundwater well fifteen-minute sample water levels
Appendix B SIR_7_5_GW_GW_WaterLevel_ESGFA138-6_20151104.xlsx Station ESGFA138-6 groundwater well fifteen-minute sample water levels
Appendix B SIR_7_5_GW_GW_WaterLevel_ESGFA138-7_20151104.xlsx Station ESGFA138-7 groundwater well fifteen-minute sample water levels
Notes:
Appendix A: Preliminary Water Table Contour Maps for Focus Areas FA-104, FA-115, FA-128, and FA-138
Appendix B: Preliminary MODFLOW Three Dimensional Groundwater Model for Focus Area FA-128 (Slough 8A)
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Table 5.1-1. Summary of hydrogeologic parameters identified from the 1980s groundwater studies and other relevant materials for the Susitna River
watershed, Alaska. (Source: SIR Study 7.5, Appendix C, Table 1.)
Source
Location or
Study Area
Alluvial
Aquifer
Sediment
Thickness (ft)
Alluvial Aquifer
Saturated
Thickness (ft)
Alluvial
Aquifer
Extent (ft)
Alluvial Aquifer
Kh (ft/d)
Alluvial
Aquifer
Kv (ft/d)
T
(ft2/d)
Storage
Coeff.
Horizontal
Hydraulic
Gradient
Acres American (1980) Devil Canyon 35
Acres American (1980)
Vee
(~ PRM 224) 125
Acres American (1980) Watana 50 - 80
Acres (1982) Watana 40 - 80
R&M Consultants (1982) Slough 8A > 9.5 226 - 1000; 328 -
3280 assumed for
calculations
0.2
0.0022 -
0.003
R&M Consultants (1982) Slough 9 > 11
R&M Consultants (1982) Slough 9B > 43 > 35 0.2 0.0033
Acres American (1983) Slough 9 100
170 - 1000; 200
assumed for
calculations 9,000 0.18
Harza-Ebasco (1983) Watana
mean 80,
locally up to
140
4.3 – 340, low
bias since only
fine grained
sediments tested
Harza-Ebasco (1984)
Slough 8A to 11,
Middle Susitna
River 100 3000^ 67 6,700
0.2
(unconf);
0.0002
(conf) 0.003
Harza-Ebasco (1984)
Talkeetna Fire
Hall > 100 > 70 84
1858 -
5900*
Harza-Ebasco (1984)
Talkeetna Area
Wells
22 - 133 (mean
57)
334 -
1070
Harza-Ebasco (1984)
Middle Susitna
River Valley
Walls 500 0.014 7.1
0.3
R&M Consultants (1985) Slough 9 0.15 - 31 0.2 - 92
R&M Consultants &
Woodward-Clyde (1985)
Gold Creek
Railway Bridge 100
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Source
Location or
Study Area
Alluvial
Aquifer
Sediment
Thickness (ft)
Alluvial Aquifer
Saturated
Thickness (ft)
Alluvial
Aquifer
Extent (ft)
Alluvial Aquifer
Kh (ft/d)
Alluvial
Aquifer
Kv (ft/d)
T
(ft2/d)
Storage
Coeff.
Horizontal
Hydraulic
Gradient
Penn Jersey Drilling (2007) Curry > 120 > 70 123 7600
USGS (2013)
Lower Susitna
Basin 250 - 400 16.9 - 19.2
1
(riverbed
sediments
)
0.004 -
0.006
Notes:
1 Kh = horizontal hydraulic conductivity; Kv = vertical hydraulic conductivity; T = transmissivity.
2 Bold values are measured values, italicized values are either assumed, estimated, or calibrated values.
3 Vertical hydraulic gradient data were presented, and therefore are not tabulated.
4 Interpretation of valley-fill sediment extent was based on aerial photos between Slough 11 and 8A.
5 See text Section 5.2 for a discussion of transmissivity interpretations.
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Table 5.5-1. Groundwater and Surface Water Field Stations and MODFLOW Calibration Targets. (Source:
SIR Study 7.5, Appendix B, Table 4-1.)
Field Station Full Name
Field Station
Short Name Station Type
Steady State
Target Transient Target
ESGFA128-10-W1 128-10-W1 Groundwater well No No
ESGFA128-11-W1 128-11-W1 Groundwater well Yes Yes
ESGFA128-12 128-12-W1 Groundwater well No No
ESGFA128-13-W1 128-13-W1 Groundwater well Yes Yes
ESGFA128-13-W2 128-13-W2 Groundwater well No No
ESGFA128-18-W1 128-18-W1 Groundwater well Yes Yes
ESGFA128-19-W1 128-19-W1 Groundwater well Yes Yes
ESGFA128-20-W1 128-20-W1 Groundwater well No No
ESGFA128-21-W1 128-21-W1 Groundwater well Yes Yes
ESGFA128-23-W1 128-23-W1 Groundwater well Yes Yes
ESGFA128-24-W1 128-24-W1 Groundwater well Yes Yes
ESGFA128-25-W1 128-25-W1 Groundwater well Yes Yes
ESGFA128-26-W1 128-26-W1 Groundwater well Yes Yes
ESGFA128-27-W1 128-27-W1 Groundwater well Yes Yes
ESGFA128-2-W1 128-2-W1 Groundwater well No Yes
ESGFA128-3-W1 128-3-W1 Groundwater well No No
ESGFA128-4-W1 128-4-W1 Groundwater well Yes Yes
ESGFA128-5-W1 128-5-W1 Groundwater well Yes Yes
ESGFA128-6-W1 128-6-W1 Groundwater well Yes Yes
ESGFA128-7-W1 128-7-W1 Groundwater well Yes Yes
ESGFA128-7-W2 128-7-W2 Groundwater well No No
ESMFA128-8-W1 128-8-W1 Groundwater well No No
ESGFA128-9-W1 128-9-W1 Groundwater well No No
ESGFA128-9-W2 128-9-W2 Groundwater well No No
ESSFA128-1 128-1 Surface-water gage No No
ESGFA128-11 128-11 Surface-water gage No No
ESGFA128-12 128-12 Surface-water gage No No
ESGFA128-13 128-13 Surface-water gage No No
ESSFA128-14 128-14 Surface-water gage No No
ESSFA128-15 128-15 Surface-water gage No No
ESSFA128-16 128-16 Surface-water gage No No
ESSFA128-17 128-17 Surface-water gage No No
ESGFA128-2 128-2 Surface-water gage No No
ESSFA128-22 128-22 Surface-water gage No No
ESGFA128-5 128-5 Surface-water gage No No
ESGFA128-6 128-6 Surface-water gage No No
ESGFA128-7 128-7 Surface-water gage No No
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Table 5.5-2. Model Calibration Results - shaded simulations = best fit model run. (Source: SIR Study 7.5, Appendix B, Table 5-1.)
Model Name
Model
(Steady
State or
Transient)
Parameters Adjusted during Model Calibration1 Model Calibration Statistics2
Specified
Flux
(ft^2/dy
per unit
length)
Kh
(ft/dy)
Kz
(ft/dy)
Kv
(ft/dy)
Storage
Coefficient
(S)
Residual
Mean (ft)
Residual
Standard
Deviation
(ft)
Absolute
Residual
Mean (ft)
Residual
Sum of
Squares
(ft)
Residual
Mean
Square
Error (ft)
Target
Range
(ft)
Scaled
RMSE
(%)
Susitna_SS_V12 SS 2.1 66 66 6.6 0.61 1.33 0.91 30.10 1.47 12.09 12.2
Susitna_SS_V18 SS 0.21 6 0.66 1 -0.20 1.10 0.79 17.40 1.12 12.09 9.3
Susitna_SS_V19 SS 0.21 6 0.66 6 0.18 1.07 0.80 16.50 1.09 12.09 9.0
Susitna_SS_V20 SS 0.21 66 6 6 0.63 1.34 0.93 30.60 1.48 12.09 12.2
Susitna_SS_V21 SS 0.21 100 10 10 0.69 1.35 0.96 32.00 1.51 12.09 12.5
Susitna_SS_V22 SS 0.21 20 1 1 0.12 1.28 0.84 23.10 1.28 12.09 10.6
Susitna_SS_V23 SS 0.21 10 1 1 0.02 1.18 0.82 19.50 1.18 12.09 9.8
Susitna_SS_V24 SS 0.21 10 1 6 0.44 1.14 0.81 20.70 1.22 12.09 10.1
Susitna_SS_V25 SS 0.21 66 0.1 6 0.61 1.29 0.89 28.70 1.43 12.09 11.8
Susitna_SS_V26 SS 0.21 20 2 2 0.38 1.26 0.82 24.40 1.32 12.09 10.9
Susitna_SS_V27 SS 0.21 50 5 5 0.61 1.33 0.92 29.80 1.46 12.09 12.1
Susitna_T_V19_Run1 T 0.21 6 0.66 6 0.001 -0.01 1.27 0.91 1200 1.27 13.25 9.6
Notes:
1 Kh = aquifer horizontal hydraulic conductivity; Kz = aquifer vertical hydraulic conductivity; Kv = river bed vertical hydraulic conductivity, and S =
aquifer storage coefficient (not required for steady state model).
2 Scaled RMSE = (Residual Sum of Squares)/(Target Range)
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Table 5.6-1. 2014 collected discharge measurements in Focus Areas. (Source: SIR Study 6.6, Table 5.1-14.)
Date
Flow
(cfs) Location
Reference
PRM
Northing
(feet)
Easting
(feet)
FA-104 Whiskers Slough
9/27/2014 10a Near head of right bank side channel 105.8 3,063,308 1,615,080
9/27/2014 1a Upstream connection into Slough 3B 105.4 3,062,647 1,613,263
9/27/2014 0.1a Near head of left bank side channel 104.9 3,059,123 1,613,857
9/27/2014 0.14 Near head of left bank side channel 105.2 3,060,336 1,613,509
9/27/2014 0.3a Near mouth of left bank side channel 104.9 3,058,879 1,613,582
9/27/2014 1.22b Downstream of beaver dam in Slough 3B 105.4 3,062,266 1,612,578
9/27/2014 0.07 Near head of left bank side channel 105.2 3,060,134 1,613,640
FA-113 Oxbow
9/23/2014 0.82 Mouth of Oxbow I 113.7 3,101,369 1,623,125
9/23/2014 6.20 Mouth of Gash Creek 115.1 3,107,391 1,622,840
9/23/2014 0.46 Mouth of Slash Creek 114.8 3,106,250 1,623,153
FA-115 Slough 6A
9/23/2014 0.45b Mouth of Unnamed Tributary 115.4 115.4 3,108,780 1,621,080
9/23/2014 0.15 Inflow from beaver dam at head of Slough 6A 116.1 3,112,010 1,619,438
9/23/2014 0.32 Groundwater inflow at head of Slough 6A 116.1 3,111,090 1,619,438
9/23/2014 1.04 Mouth of tributary into Slough 6A 116.0 3,111,431 1,619,417
9/23/2014 0.84b Side channel in mid-channel island 115.9 3,111,547 1,620,764
FA-128 Slough 8A
9/26/2014 1.01 Near head of Slough 8A 130.1 3,167,600 1,659,832
9/26/2014 1a Unnamed Tributary to Slough 8 A 129.9 3,166,924 1,659,026
9/26/2014 1a Unnamed Tributary to Slough 8A 130.0 3,167,209 1,659,443
9/26/2014 4.65 Downstream of beaver dam on Slough 8A 129.7 3,166,393 1,658,118
9/26/2014 10a Channel across mid-channel island 128.3 3,165,013 1,650,820
9/26/2014 0.1a Mouth of channel on south side of mid-channel island 128.6 3,164,469 1,652,751
9/26/2014 0.1a Mouth of channel on north side of mid-channel island 128.8 3,166,472 1,652,610
9/25/2014 1a Near head of channel into Slough 8A 129.5 3,166,780 1,656,565
9/25/2014 1.39 Near mouth of channel into Slough 8A 129.4 3,166,043 1,656,332
9/25/2014 9.22 Slough 8A above confluence with channel 129.4 3,165,724 1,656,500
9/25/2014 0.51 Near mouth of Slough A 128.1 3,163,824 1,650,824
9/25/2014 0.60 Head of channel across mid-channel island 128.7 3,166,031 1,652,420
9/25/2014 No flow Near head of Half-Moon Slough 128.9 3,165,827 1,653,557
9/25/2014 1.96 Near mouth of channel across mid-channel island 128.4 3,164,548 1,651,705
FA-138 Gold Creek
9/24/2014 1.69 Near head of Upper Side Channel 11 139.9 3,203,504 1,691,698
9/24/2014 2.13 Near mouth of Upper Side Channel 11 139.6 3,202,738 1,689,788
9/24/2014 60a Near head of channel into mouth of Slough 12 138.7 3,199,419 1,688,668
9/24/2014 0.1a Near mouth of Slough 12 138.8 3,199,475 1,689,142
9/24/2014 0.21 Near mouth of Slough 13 139.0 3,200,668 1,688,970
9/24/2014 1a Outlet from beaver impounded pond along right bank 139.5 3,203,481 1,688,936
9/24/2014 0.25 Near head of Slough 11 139.4 3,202,434 1,690,710
9/24/2014 0.37 Left channel downstream of beaver dam in Slough 11 138.9 3,200,220 1,690,204
9/24/2014 1.16 Middle channel downstream of beaver dam in Slough 11 138.9 3,200,235 1,690,195
9/24/2014 0.62 Right channel downstream of beaver dam in Slough 11 138.9 3,200,249 1,690,182
9/24/2014 1.56 Left channel near mouth of Slough 11 138.7 3,199,033 1,689,404
9/24/2014 1.65 Right channel near mouth of Slough 11 138.7 3,198,943 1,689,382
FA-141 Indian River
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Date
Flow
(cfs) Location
Reference
PRM
Northing
(feet)
Easting
(feet)
9/25/2014 0.1a Mouth of Slough 17 142.3 3,211,169 1,698,990
FA-144 Slough 21
9/24/2014 14.3 Mouth of Unnamed Tributary 144.6 144.5 3,217,382 1,708,369
9/24/2014 10.3 Side Channel 21 near mouth of Unnamed Tributary 144.6 144.6 3,217,686 1,708,391
9/24/2014 1.25 Mouth of channel across mid-channel island 144.9 3,218,990 1,709,017
9/24/2014 No flow Mouth of channel across mid-channel island 145.0 3,219,661 1,709,360
9/23/2014 300a Mouth of channel across mid-channel island 144.5 3,217,850 1,707,901
9/24/2014 1a Near inlet berm into channel on mid-channel island 145.5 3,221,584 1,711,078
9/24/2014 0.01a Near head of channel across mid-channel island 145.5 3,221,237 1,711,539
9/24/2014 0.23 Downstream of beaver dam in Slough 21 145.2 3,219,949 1,710,390
9/24/2014 0.90 Slough 21 145.1 3,219,801 1,710,244
9/24/2014 1.50a Mouth of channel across mid-channel island 145.1 3,219,801 1,709,815
Notes:
a = estimated flow
b = flow measured with current meter
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10. FIGURES
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Figure 3-1. Susitna Watershed basin boundaries, showing the Project designation of upper, Middle and Lower river segments (Source: ISR Study 7.5,
Figure 3-1).
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Figure 3-2. Susitna Watershed Middle River Segment, with geomorphic reaches and Focus Areas indicated (Source: ISR Study 7.5, Figure 3-12.)
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Figure 3-3. Susitna Watershed Lower River Segment, with geomorphic reaches indicated (Source: ISR Study 7.5, Figure 3-3).
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Figure 4.5-1. FA-128 (Slough 8A) Focus Area with groundwater and surface water monitoring locations (Source: ISR Study 7.5, Appendix B, Figure 3-
3).
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Figure 4.5-2. Groundwater Model Extent and Simulated Features in FA-128 Area (Source: ISR Study 7.5, Appendix B, Figure 4-2).
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Figure 5.4-1. Example delineation of Riverine Dominated, Riverine-Upland Transitional, and Upland Dominated. (Source: SIR Study 7.5, Appendix D,
presentation slide 30.)
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Figure 5.5-1. Primary riparian cross section at FA-115 (Slough 6A) showing location of groundwater wells,
surface-water measurement locations, and the measured water levels on April 24-25, 2014, with inferred
water table. (Source: GWS and R2 2014a - Figure 22.)
Figure 5.5-2. Groundwater elevations and surface-water levels for selected stations in FA-115 (Slough 6A)
representing upland groundwater conditions and lower groundwater wells affected by riverine processes.
(Source: GWS and R2 2014a - Figure 23.)
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Figure 5.5-3. Cross-section profile of the Upper Riparian Transect in FA-128 (Slough 8A) showing the land
surface profile, location of groundwater wells and surface water measuring points on Upper Side Channel 8A
and Slough 8A. Water levels are shown for the April 20-23, 2014. Water levels in Upper Side Channel 8A are
ice affected. (Source: GWS and R2 2014a - Figure 26.)
Figure 5.5-4. Water level data for Upper Side Channel 8A, Slough 8A, and groundwater wells between the
two surface-water features on the Upper Riparian Transect in FA-128 (Slough 8A). (Source: GWS and R2
2014a - Figure 27.)
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Figure 5.5-5. Primary riparian cross section at FA-138 (Gold Creek) showing locations of surface-water
measurement locations, and typical upland features that indicate shallow groundwater conditions. Water
levels are shown for the cross-section survey date of 9/14/2014. (Source: GWS and R2 2014a - Figure 24.)
Figure 5.5-6. Surface-water levels for stations in the FA-138 (Gold Creek) riparian transect. Major
hydrologic periods are indicated to show how the variation in water levels relate to the climate and
hydrologic processes relevant to these periods. (Source: GWS and R2 2014a - Figure 25.)
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Figure 5.5-7. Monitored versus Simulated Steady State Groundwater Elevations. (Source: SIR Study 7.5, Appendix B, Figure 5-1.)
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Figure 5.5-8. Simulated Steady Stage Groundwater Elevations and Model Target Residuals in FA-128 Area. (Source: SIR Study 7.5, Appendix B,
Figure 5-2.)
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Figure 5.5-9. Simulated Steady Stage Groundwater Elevations with Flooded and Dry Model Cells Shown. (Source: SIR Study 7.5, Appendix B, Figure
5-3.)
2014-2015 STUDY IMPLEMENTATION REPORT GROUNDWATER STUDY (STUDY 7.5)
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Figure 5.5-10. Monitored versus Simulated Steady State Groundwater Elevations (Station 128-13). (Source: SIR Study 7.5, Appendix B, Figure 5-4.)
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Figure 5.5-11. Monitored versus Simulated Steady State Groundwater Elevations (Station 128-4). (Source: SIR Study 7.5, Appendix B, Figure 5-5.)
2014-2015 STUDY IMPLEMENTATION REPORT GROUNDWATER STUDY (STUDY 7.5)
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Figure 5.5-12. Monitored versus Simulated Transient Head Difference between Surface water and Groundwater at Target Station 128-6. (Source: SIR
Study 7.5, Appendix B, Figure 5-6.)
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Figure 5.5-13. Monitored versus Simulated Transient Flux beneath Slough 8A at Target Station 128-6. (Source: SIR Study 7.5, Appendix B, Figure 5-
10.)
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Figure 5.5-14. FA-104 (Whiskers Slough), showing water-level elevation contours for Late Fall – October 9, 2013, Susitna River. (Source: SIR Study
7.5, Appendix A, Figure 5.1-3.)
2014-2015 STUDY IMPLEMENTATION REPORT GROUNDWATER STUDY (STUDY 7.5)
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Figure 5.5-15. FA-115 (Slough 6A), showing water-level elevation contours for Late Fall – October 9, 2013, Susitna River. (Source: SIR Study 7.5,
Appendix A, Figure 5.2-2.)
2014-2015 STUDY IMPLEMENTATION REPORT GROUNDWATER STUDY (STUDY 7.5)
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Figure 5.5-16. FA-128 (Slough 8A), showing water-level elevation contours for Late Fall – October 9, 2013, Susitna River. (Source: SIR Study 7.5,
Appendix A, Figure 5.3-3.)
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Figure 5.5-17. FA-138 (Gold Creek), showing water-level elevation contours for Late Fall – October 9, 2014, Susitna River. (Source: SIR Study 7.5,
Appendix A, Figure 5.4-2.)
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Figure 5.6-1. Groundwater Station ESGFA128-13 groundwater levels in wells adjacent to Middle Side
Channel 8A and surface-water stage in Middle Side Channel 8A, and groundwater levels from wells at
ESGFA128-20 and ESGFA128-21. (Source: GWS and R2 2014b - Figure 4.1-14.)
Figure 5.6-2. Groundwater Station ESGFA128-13 groundwater temperature in wells adjacent to Middle Side
Channel 8A and surface-water temperature in Middle Side Channel 8A, and groundwater temperature from
wells at ESGFA128-20 and ESGFA128-21. (Source: GWS and R2 2014b - Figure 4.1-15.)
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Figure 5.6-3. Downwelling example in Middle Side Channel 8A in FA-128 (Slough 8A) showing groundwater
and surface-water levels, stream-bed temperatures, and thermal profile of the stream bed conditions through
the major hydrologic periods. (Source: GWS and R2 2014b - Figure 4.3-32.)
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Figure 5.6-4. Upwelling example in Upper Side Channel 11 in FA-138 (Gold Creek) showing groundwater
and surface-water levels, stream-bed temperatures, and thermal profile of the stream bed conditions through
the major hydrologic periods. (Source: GWS and R2 2014b - Figure 4.3-33.)