HomeMy WebLinkAboutSuWa71Alaska Resources Library & Information Services
Susitna-Watana Hydroelectric Project Document
ARLIS Uniform Cover Page
Title:
Technical memorandum, riparian physical process modeling
SuWa 71
Author(s) – Personal:
Author(s) – Corporate:
Prepared by R2 Resource Consultants, Inc.
AEA-identified category, if specified:
2012 Environmental Studies
AEA-identified series, if specified:
Series (ARLIS-assigned report number):
Susitna-Watana Hydroelectric Project document number 71
Existing numbers on document:
Published by:
[Anchorage, Alaska : Alaska Energy Authority, 2013]
Date published:
March 2013
Published for:
Prepared for Alaska Energy Authority
Date or date range of report:
Volume and/or Part numbers:
Final or Draft status, as indicated:
Document type:
Technical memorandum
Pagination:
iv, 29 p.
Related work(s):
Pages added/changed by ARLIS:
Notes:
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)
Technical Memorandum
Riparian Physical Process Modeling
Prepared for
Alaska Energy Authority
Prepared by
R2 Resource Consultants, Inc.
March 2013
RIPARIAN PHYSICAL PROCESS MODELING
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page i March 2013
TABLE OF CONTENTS
1. Introduction ........................................................................................................................1
2. Riparian IFS Physical Process Modeling Elements ........................................................2
2.1. Climate, Hydrology and Seed Dispersal – Degree-day Climate and
Recruitment Box Models ...................................................................................2
2.2. Ice Processes and Floodplain Vegetation ..........................................................3
2.3. Geomorphology and Floodplain Vegetation ......................................................4
2.4. Surface Water / Groundwater Regime and Floodplain Vegetation ...................5
2.4.1. Groundwater and Surface Water Interaction Modeling .................. 5
3. References ...........................................................................................................................6
4. Tables ..................................................................................................................................8
5. Figures ...............................................................................................................................16
LIST OF TABLES
Table 1. Integration of Riparian IFS physical modeling schedule with other studies. .................. 9
Table 2. Information and products required by the Riparian IFS Study from other studies. ....... 11
Table 3. Information and products the Riparian IFS Study will provide to other studies. ........... 12
Table 4. Primary output variables for which values are taken directly from the 1-D and 2-D
mobile-boundary models and relevance to other studies. ..................................................... 13
Table 5. Key variables needed for the impact assessments for which results are obtained through
additional analysis of predictions taken directly from the 1-D and 2-D mobile-boundary
models. .................................................................................................................................. 14
LIST OF FIGURES
Figure 1. Susitna River Project Area. .......................................................................................... 17
Figure 2. Study interdependencies for Riparian Instream Flow Study. ....................................... 18
Figure 3. Floodplain Vegetation Study Synthesis, Focus Area to Riparian Process Domain
Scaling & Project Operations Effects Modeling 8.6.3.7. ...................................................... 19
Figure 4. Seed Dispersal, Hydrology and Climate Synchrony Study8.6.3.3.1. ........................... 20
Figure 5. The riparian “Recruitment Box Model” describing seasonal flow pattern, associated
river stage (elevation), and flow ramping necessary for successful cottonwood and willow
seedling establishment (from Amlin and Rood 2002; Rood et al., 2005). Cottonwood
RIPARIAN PHYSICAL PROCESS MODELING
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page ii March 2013
species (Populus deltoides), willow species (Salix exigua). Stage hydrograph and seed
release timing will vary by region, watershed, and plant species. ........................................ 21
Figure 6. Cottonwood (Populus) life history stages: seed dispersal and germination, sapling to
tree establishment. Cottonwood typically germinates on newly created bare mineral soils
associate with lateral active channel margins and gravel bars. Note proximity of summer
baseflow and floodplain water table (Braatne et al. 1996). .................................................. 22
Figure 7. River Ice-Floodplain Vegetation Establishment and Recruitment 8.6.3.4. .................. 23
Figure 8. Relationship of ice observations to other studies. ........................................................ 24
Figure 9. Floodplain Erosion, Sediment Deposition & Floodplain Vegetation Study 8.6.3.5. ... 25
Figure 10. Study interdependencies for the Fluvial Geomorphology Modeling Study. ............... 26
Figure 11. Floodplain Vegetation Groundwater & Surface Water Study 8.6.3.6. ....................... 27
Figure 12. Study interdependencies for the Groundwater Study. ................................................ 28
RIPARIAN PHYSICAL PROCESS MODELING
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page iii March 2013
LIST OF ACRONYMS AND SCIENTIFIC LABELS
Term Definition
Active floodplain The flat valley floor constructed by river during lateral channel migration and
deposition of sediment under current climate conditions.
Aggradation
1. Geologic process in which inorganic materials carried downstream are deposited
in streambeds, floodplains, and other water bodies resulting in a rise in elevation in
the bottom of the water body. 2. A state of channel disequilibrium, whereby the
supply of sediment exceeds the transport capacity of the stream, resulting in
deposition and storage of sediment in the active channel.
Alluvial Relating to, composed of, or found in alluvium.
Bank
The sloping land bordering a stream channel that forms the usual boundaries of a
channel. The bank has a steeper slope than the bottom of the channel and is
usually steeper than the land surrounding the channel.
Braid Pattern of two or more interconnected channels typical of alluvial streams.
Channel A natural or artificial watercourse that continuously or intermittently contains water,
with definite bed and banks that confine all but overbank streamflows.
Confinement Ratio of valley width (VW) to channel width (CW). Confined channel VW:CW <2;
Moderately confined channel VW:CW 2-4; Unconfined channel VW:CW >4.
Confluence The junction of two or more streams.
Cubic feet per second (cfs)
A standard measure of the total amount of water passing by a particular location of
a river, canal, pipe or tunnel during a one second interval. One cfs is equal to
7.4805 gallons per second, 28.31369 liters per second, 0.028 cubic meters per
second, or 0.6463145 million gallons per day (mgd). Also called second-feet.
Deposition The settlement or accumulation of material out of the water column and onto the
streambed.
Disturbance regime
Floodplain vegetation disturbance types found within the Susitna River Study Area
corridor include: channel migration (erosion and depositional processes), ice
processes (shearing impacts, flooding and freezing), herbivory (beaver, moose, and
hare), wind, and, to an infrequent extent, fire. Floodplain soil disturbance is
primarily ice shearing and sediment deposition.
Drainage area The total land area draining to any point in a stream. Also called catchment area,
watershed, and basin.
Embeddedness
The degree that larger particles (boulders, large wood, rubble, or gravel) are
surrounded or covered by fine sediment. Usually measured in classes according to
percent of coverage.
Floodplain
1. The area along waterways that is subject to periodic inundation by out-of-bank
flows. 2. The area adjoining a water body that becomes inundated during periods of
over-bank flooding and that is given rigorous legal definition in regulatory programs.
3. Land beyond a stream channel that forms the perimeter for the maximum
probability flood. 4. A relatively flat strip of land bordering a stream that is formed by
sediment deposition. 5. A deposit of alluvium that covers a valley flat from lateral
erosion of meandering streams and rivers.
Geomorphic mapping
A map design technique that defines, delimits and locates landforms. It combines a
description of surface relief and its origin, relative age, and the environmental
conditions in which it formed. This type of mapping is used to locate and
differentiate among relief forms related to geologic structure, internal dynamics of
the lithosphere, and landforms shaped by external processes governed by the bio-
climate environment.
RIPARIAN PHYSICAL PROCESS MODELING
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page iv March 2013
Term Definition
Geomorphology The scientific study of landforms and the processes that shape them.
Gradient The rate of change of any characteristic, expressed per unit of length (see Slope).
May also apply to longitudinal succession of biological communities.
Gravel Substrate particles between 0.1 and 3.0 inches in size, larger than sand and smaller
than cobble.
Groundwater In general, all subsurface water that is distinct from surface water; specifically, that
part which is in the saturated zone of a defined aquifer.
Habitat
The environment in which the fish live, including everything that surrounds and
affects its life, e.g., water quality, bottom, vegetation, associated species (including
food supplies). The locality, site and particular type of local environment occupied
by an organism.
Ice dam A stationary accumulation of fragmented ice or frazil that restricts or blocks a stream
channel.
Large woody debris (LWD) Pieces of wood larger than 10 feet long and 6 inches in diameter, in a stream
channel. Minimum sizes vary according to stream size and region.
Instream flow The rate of flow in a river or stream channel at any time of year.
Pool Part of a stream with reduced velocity, often with water deeper than the surrounding
areas, which is usable by fish for resting and cover.
Riparian Pertaining to anything connected with or adjacent to the bank of a stream or other
body of water.
Riparian vegetation Vegetation that is dependent upon an excess of moisture during a portion of the
growing season on a site that is perceptively more moist than the surrounding area.
River A large stream that serves as the natural drainage channel for a relatively large
catchment or drainage basin.
River mile The distance of a point on a river measured in miles from the river's mouth along
the low-water channel.
Scour The localized removal of material from the streambed by flowing water. This is the
opposite of fill.
Sediment Solid material, both mineral and organic, that is in suspension in the current or
deposited on the streambed.
Three Rivers Confluence
The confluence of the Susitna, Chulitna, and Talkeetna rivers at Susitna River Mile
(RM) 98.5 represents the downstream end of the Middle River and the upstream
end of the Upper River.
RIPARIAN PHYSICAL PROCESS MODELING
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 1 March 2013
1. INTRODUCTION
The Alaska Energy Authority (AEA) is preparing a license application that will be submitted to
the FERC for the Susitna-Watana Hydroelectric Project (Project) using the Integrated Licensing
Process. The Project is located at RM 184 on the Susitna River, an approximately 300-mile long
river in the Southcentral region of Alaska (Figure 1). As currently envisioned, the Project would
include a large dam with an approximately 35,000-acre, 41-mile long reservoir. Project
construction and operation would have an effect on the flows downstream of the dam site, the
degree of which will ultimately depend on final Project design and operations. Key flow
changes will likely occur in the form of load following during the portion of the year when the
reservoir is not full. Seasonal variation will result in flows higher during the winter months and
lower during summer reservoir refill, June through August. The alteration in flows might
influence downstream resources and processes, including fish and aquatic biota, and their
habitats, and riparian and wildlife communities. Alterations to channel form and function might
include changes in natural flow regime, sediment transport, large woody debris recruitment and
transport, water quality, groundwater/surface water interactions, and ice dynamics.
Potential operational flow-induced effects of the Project will be evaluated as part of the licensing
process, through studies spanning 2012 through 2014. The evaluation is important from both the
impact minimization and operational optimization perspectives. In both cases, AEA desires to
move from study results to decisions affecting flow releases in terms of (i) timing (seasonal,
daily, diurnal), (ii) steady flow magnitudes, and (iii) magnitude and rate of change of unsteady
flow. These three aspects of flow regime influence physical habitat quantity and quality and
geomorphic processes, which in turn influence carrying capacity and overall suitability for target
fish species and riparian vegetation.
The goal of the 2013–2014 Riparian Instream Flow Study (hereafter Riparian IFS) is to provide a
quantitative, spatially-explicit model to predict potential impacts to downstream floodplain
vegetation from Project operational flow modification of natural Susitna River flow, sediment,
and ice process regimes. To meet this goal, a physical and vegetation process modeling
approach will be used. First, existing Susitna River groundwater and surface water (GW/SW)
flow, sediment and ice process regimes will be measured, and modeled. Second, floodplain plant
community composition and structure will be characterized and mapped. Third, probabilistic
models of floodplain vegetation type and physical process regimes will be developed. Fourth,
predictive models will be developed to assess potential Project operational impacts to floodplain
plant communities and provide operational guidance to minimize these impacts. Fifth, the
predictive models will be applied throughout the Project study area and the results, using
Geographic Information System (GIS), will be displayed in a series of maps of potential
floodplain vegetation changes under alternative operational flow scenarios.
This technical memorandum provides a summary overview of the various climatic, seed
dispersal, ice process, geomorphologic, and groundwater physical process modeling studies
conducted in support of the Riparian IFS. The Riparian IFS Revised Study Plan (hereafter RSP),
Section 8.6, provides complete details of both physical and vegetation studies, however, all of
the various supporting physical modeling elements are found in their respective RSP Sections.
For a complete picture of the physical modeling studies supporting the Riparian IFS the reader
must consult all of the following RSPs: Riparian IFS (Section 8.6); Instream Flow Study
RIPARIAN PHYSICAL PROCESS MODELING
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 2 March 2013
(Section 8.5); Geomorphology Study (Section 6.5); Fluvial Geomorphology Modeling below
Watana Study Dam Study (Section 6.6); Groundwater Study (Section 7.5); Ice Processes in the
Susitna River (Section 7.6); and Riparian Vegetation Study Downstream of the Proposed Watana
Dam (Section 11.6).
The objective of this technical memorandum is to bring together for the reader, in one document:
(1) a description of the various Riparian IFS physical process modeling elements, (2) illustrations
of how each model contributes to specific Riparian instream flow studies, and (3) an integrated
schedule of model deliverables. Table 1 provides the schedules for completion of studies that
will be integrated into the Riparian IFS modeling. Tables 2 and 3 outline physical modeling
input and output parameters that will be needed from or provided to other studies.
2. RIPARIAN IFS PHYSICAL PROCESS MODELING ELEMENTS
The Riparian IFS interdependencies, including physical process modeling elements, are
presented in Figure 2. In addition to physical process modeling, a series of descriptive and
analytical studies comprise the overall Riparian IFS (Figure 2). The logical sequencing of all of
the analytical and modeling studies, and how they feed into final Project operations effects
modeling, is presented in Figure 3.
In this Section, Riparian IFS physical process modeling elements will be discussed as presented
in RSP Section 8.6 beginning with Section 8.6.3.3 ‘degree-day’ climate and ‘recruitment box’
modeling in support of characterization of seed dispersal and seedling establishment
groundwater and surface water hydroregime requirements. Next, RSP Section 8.6.3.4 ice
process modeling characterization of the role of river ice in the establishment and recruitment of
dominant floodplain vegetation is presented followed by RSP Section 8.6.3.5 fluvial geomorphic
bed-evolution and sediment transport modeling characterization of Susitna River floodplain
surfaces, the physical template for vegetation establishment; and finally, RSP Section 8.6.3.6
groundwater and surface water interaction modeling of critical hydroregimes necessary for
floodplain vegetation establishment and maintenance is presented. RSP Section 8.6.3.7 Project
operations effects modeling approach will not be presented here as the modeling approach will
be developed in detail during Q1 through Q4 2013.
2.1. Climate, Hydrology and Seed Dispersal – Degree-day Climate
and Recruitment Box Models
The goal of Riparian IFS RSP Section 8.6.3.3 climate, hydrology and seed dispersal study is to
first, characterize groundwater and surface water hydroregime requirements for poplar (Populus
balsamifera) and willow (Salix spp.) species seed dispersal and seedling establishment and
second, to develop a predictive model of potential Project operational impacts to seedling
establishment.
Specific study objectives are to:
1. Measure cottonwood and select willow species seed dispersal timing.
2. Model local Susitna River valley climate, and associated seasonal peak flows, relative to
cottonwood and willow seed dispersal.
RIPARIAN PHYSICAL PROCESS MODELING
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 3 March 2013
3. Develop a recruitment box model of seed dispersal timing, river flow regime, and
cottonwood and willow seed dispersal and establishment.
Physical process modeling in support of this study include: (1) ‘degree-day’ climate model and
(2) recruitment box model. The degree-day model incorporates seed release observations and
continuous air temperature records from the Susitna River floodplain sites. The degree-day
model characterizes annual plant development stages such as onset of vegetative and
reproductive growth (seed release) as a cumulative daily heat load above a specific threshold
temperature (Stella et al. 2006). The degree-day model will be parameterized by empirically
calculating the heat-load that best predicts the onset of peak poplar and willow seed release. The
model is based upon accurate local temperature records (Stella et al. 2006). The degree-day
climate model element of the climate, hydrology and seed dispersal study is shown in Figure 4.
The “Recruitment Box Model,” an empirical model, captures cottonwood and willow seed
dispersal, flow response and establishment requirements (Figure 5; Mahoney and Rood 1998;
Rood et al. 2003). The empirical model characterizes seasonal flow pattern, associated river
stage (elevation), and flow down ramping rates necessary for successful cottonwood and willow
seedling establishment (Figure 5 and Figure 6). The recruitment box model is based upon the
results of the seed release study and flow routing physical process model (Aquatic IFS RSP
Section 8.5.4.3). Study interdependencies are presented in Figure 4.
2.2. Ice Processes and Floodplain Vegetation
The goal of Riparian RSP Section 8.6.3.4 river ice and floodplain vegetation interaction study is
to characterize the role of river ice in the establishment and recruitment of dominant floodplain
vegetation. Although the role of fluvial disturbance (erosion and sediment deposition) in the
development of floodplain vegetation has been well investigated (Naiman et al. 1998; Rood et al.
2007), the role of river ice processes has seen little study (Engstrom et al. 2011; Prowse and
Beltaos 2002; Prowse and Culp 2003; Rood et al. 2007). Impacts of ice-related processes to
riparian habitat typically occur during break-up when ice scours channel and floodplain surfaces
(Prowse and Culp 2003). During break-up, ice accumulation in meander bends can create ice
dams elevating backwater surfaces, forcing meltwater to bypass the bend and scour a new
meander cutoff, generating new side channels (Prowse and Culp 2003). Elevated backwater,
resulting from ice dams, may also float ice blocks onto and through vegetated floodplain
surfaces, causing mechanical shearing effects including tree ice-scarring and abrasion, removal
of floodplain vegetation, and disturbance of floodplain soils (Engstrom et al. 2011; Rood et al.
2007; Prowse and Culp 2003).
The objective of the ice effects vegetation study is to quantitatively describe floodplain plant
community composition, abundance, age, and spatial pattern to assess the role and degree of
influence ice processes have on Susitna River floodplain vegetation.
Specific objectives of the ice processes floodplain vegetation interaction and modeling study are
to:
1. Develop an integrated model of ice process interactions with floodplain vegetation.
2. Conduct primary research to identify the effects of ice on floodplain vegetation within
mapped Susitna River ice floodplain impact zones.
RIPARIAN PHYSICAL PROCESS MODELING
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 4 March 2013
3. Provide Project operational guidance on potential effects of operations flow on ice
formation and floodplain vegetation development.
The ice process study (RSP Section 7.6) will develop and calibrate a dynamic thermal and ice
processes model. The model will provide maps of ice cover progression and decay, ice cover
extent and thickness, and effects of Project operational flow fluctuation on ice cover
development and stability. The ice process modeling study will provide the riparian ice
vegetation study with estimated horizontal and vertical zones of ice formation, ice thickness, and
floodplain impact zones. Model output will be used in conjunction with the empirical survey
data to (1) empirically test model output with mapped riparian domains of ice floodplain
vegetation interaction, and (2) model changes in locations and types of ice formation processes
due to Project operational flow regime.
Study interdependencies are presented in Figures 7 and 8.
2.3. Geomorphology and Floodplain Vegetation
The Fluvial Geomorphology Modeling Study will support Riparian IFS RSP Section 8.6.3.5
characterization of the role of fluvial geomorphologic processes (erosion and sedimentation) in
the formation of floodplain surfaces, soils and vegetation. The geomorphology study consists of
two individual studies: (1) Geomorphology (RSP Section 6.5) investigation of historical and
current geomorphology and geomorphic/geologic controls of the Susitna River by geomorphic
reach using available information and additional information collected as part of the licensing
effort; and (2) Fluvial Geomorphology Modeling Study (Section 6.6) that will apply 1-D and 2-D
hydraulic and bed evolution models to quantify geomorphic processes in the existing river,
equilibrium status of identified reaches and associated, potential Project effects on river
geomorphology, and thus, habitats, including floodplain development. Finally, the results of the
fluvial geomorphology modeling study will support the development of a predictive model to
assess potential Project effects on riparian seedling establishment.
The dynamics of channel migration—sediment transport, and resulting floodplain erosion and
sediment depositional patterns—is a critical physical process directly affecting floodplain soil
development, and vegetation establishment, recruitment, and spatial location, throughout alluvial
segments of the river network (Richards et al. 2002). The life history strategies and
establishment requirements of floodplain plant species are adapted to natural flow and sediment
regimes (Braatne et al. 1996; Naiman et al. 1998; Karrenberg et al. 2002). As such, alterations of
natural hydrologic and sediment regime seasonal timing, magnitude, frequency, and duration
may have effects on plant species establishment, survival, and recruitment (Braatne et al. 1996).
The goal of this study is to characterize the role of erosion and sediment deposition in evolution
of floodplain plan form, soil development, and trajectory of plant community succession,
especially vegetation establishment stage. This study will investigate the geomorphic evolution
of the Study Area floodplain with an emphasis on floodplain sediment deposition, stratigraphy,
soil development, and associated plant community succession. Historic sediment deposition
rates will be measured throughout the Study Area river network and variations in floodplain
forming processes will be assessed. Finally, a predictive model will be developed with the
Fluvial Geomorphology Study (see Section 6.6) to assess Project operational effects on
hydrologic and sediment regimes, and effects on soil and floodplain plant community
development.
RIPARIAN PHYSICAL PROCESS MODELING
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 5 March 2013
The fluvial geomorphology modeling approach (see RSP Section 6.6) is based upon (1) 1-D / 2-
D modeling of river discharge and stage, (2) 1-D / 2-D sediment transport model, and (3) channel
bed evolution model.
Study interdependencies are presented in Figures 9 and 10. Data input and output from 1-D and
2-D models are presented in Tables 4 and 5. The objectives of the study are as follows:
1. Measure the rates of channel migration, and floodplain vegetation disturbance or
turnover, throughout the Study Area.
2. Measure the rates of sediment deposition, and floodplain development, throughout the
Study Area.
3. Assess / model how Project operations will effect changes in the natural sediment
regime, floodplain depositional patterns, and soil development throughout the Study
Area.
4. Assess / model how Project operations changes in sediment transport and soil
development will affect floodplain plant community succession.
2.4. Surface Water / Groundwater Regime and Floodplain
Vegetation
The Groundwater Study (RSP Section 7.5) will support the Riparian IFS in providing a surface
water/ groundwater (SW/GW) interaction model at select Focus Area sites. The SW/GW model
will characterize and model natural floodplain vegetation groundwater and surface water
hydroregimes and be the basis for developing a predictive model to assess potential Project
operational changes to natural hydroregime and floodplain vegetation.
The goal of the floodplain vegetation GW/SW interaction modeling effort is to empirically
sample, statistically characterize, and model the relationship between floodplain groundwater
and surface water hydroregime and associated floodplain plant communities and to use this
model to predict Project operation effects on floodplain vegetation throughout the Study Area.
This investigation will (1) characterize dominant floodplain woody plant species establishment
and maintenance life stage water sources through stable isotope analyses of groundwater, soil
water, and xylem water; (2) develop a floodplain GW/SW model; and (3) develop floodplain
vegetation-flow response models.
2.4.1. Groundwater and Surface Water Interaction Modeling
A physical model of GW/SW interactions will be developed for each of five Focus Area sites, of
riparian concern, to model floodplain plant community GW/SW relationships. Developing
conceptual model and numerical representations of the GW/SW interactions, coupled with
important processes in the unsaturated zone, will help evaluate natural variability in the Susitna
River riparian floodplain plant communities, and assesses how various Project operations may
potentially result in alterations of floodplain plant community types, as well as improve the
understanding of what controlled fluctuations of flow conditions would result in minimal riparian
changes.
MODFLOW (USGS 2005), the most widely used groundwater model in the U.S. and worldwide,
will be used. Additionally, RIP-ET (riparian−evapotranspiration MODFLOW package;
RIPARIAN PHYSICAL PROCESS MODELING
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 6 March 2013
Maddock et al. 2012), developed to help better represent plant transpiration processes in the
unsaturated zone, will be utilized to more accurately calculate evapotranspiration, separating out
plant transpiration from evaporation processes.
The riparian vegetation GW/SW interactions study approach and design will be integrated with
the findings of the riparian plant community succession, geomorphology, and ice processes
modeling to characterize physical processes and riparian plant community relationships. The
results of these studies will be used to assess (1) changes to physical processes due to dam
operations, and (2) response of riparian plant communities to operations alterations of natural
flow and ice processes regimes.
Study interdependencies are presented in Figures 11 and 12. The detailed GW/SW interaction
study approach and methods are presented in the Groundwater Study, RSP Section 7.5.
3. REFERENCES
Amlin N.M. and Rood S.B. 2002. Comparative tolerances of riparian willows and cottonwoods
to water-table decline. Wetlands22: 338-346.
Braatne, J.H., S.B. Rood and P.E. Heilman. 1996. Life history, ecology, conservation of
riparian cottonwoods in North America. In: Biology of Populus and its Implications for
Management and Conservation (Eds. R.F. Stettler, H.D. Bradshaw, P.E. Heilman and T.M.
Hinckley), pp. 57-86. NRC Research Press, Ottawa.
Engstrom, J., R. Jansson, C. Nilsson and C. Weber. 2011. Effects of river ice on riparian
vegetation. Freshwater biology 56: 1095-1105.
Karrenberg, S., P.J. Edwards and J. Kollmann. 2002. The life history of Salicaceae living in the
active zone of floodplains. Freshwater Biology 47: 733-748.
Mahoney, J.M. and S.B. Rood. 1998. Stream flow requirements for cottonwood seedling
recruitment−an integrative model. Wetlands 18: 634-645.
Maddock, Thomas, III, Baird, K.J., Hanson, R.T., Schmid, Wolfgang, and Ajami, Hoori. 2012.
RIP-ET: A riparian evapotranspiration package for MODFLOW-2005: U.S. Geological
Survey Techniques and Methods 6-A39, 76 p.
Naiman, R.J., K.L. Fetherston, S.J. McKay, and J. Chen. 1998. Riparian forests. Chapter 12 In
Naiman, R.J. and R.E. Bilby, River Ecology and Management, Lessons from the Coastal
Pacific Northwest. Springer, New York.
Prowse, T.D. and S. Beltaos. 2002. Climatic control of river-ice hydrology: a review.
Hydrological Processes 16: 805-822.
Prowse, T.D. and J.M. Culp. 2003. Ice breakup: a neglected factor in river ecology. Canadian
Journal of Civil Engineering 30: 128-144.
RIPARIAN PHYSICAL PROCESS MODELING
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 7 March 2013
Richards, K., J. Brasington and F. Hughs. 2002. Geomorphic dynamics of floodplains:
ecological implications and a potential modeling strategy. Freshwater Biology 47: 559-579.
Rood, S.B., J.H. Braatne and F.M.R. Hughes. 2003. Ecophysiology of riparian cottonwoods:
stream flow dependency, water relations and restoration. Tree Physiology 23: 1113-1124.
Rood, S.B., L.A. Goater, J.M. Mahoney, C.M. Pearce and D.G. Smith. 2007. Floods, fire, and
ice: disturbance ecology of riparian cottonwoods. Canadian Journal of Botany 85: 1019-
1032.
Stella, J.C., J.J. Battles, B.K. Orr, and J.R. McBride. 2006. Synchrony of seed dispersal,
hydrology and local climate in a semi-arid river reach in California. Ecosystems 9: 1200-
1214.
USGS (U.S. Geological Survey). 2005. MODFLOW-2005, The U.S. Geological Survey
modular ground-water model—the Ground-Water Flow Process: U.S. Geological Survey
Techniques and Methods 6-A16.
RIPARIAN PHYSICAL PROCESS MODELING
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 8 March 2013
4. TABLES
RIPARIAN PHYSICAL PROCESS MODELING
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 9 March 2013
Table 1. Integration of Riparian IFS physical modeling schedule with other studies.
Activity 2012 2013 2014 2015
1 Q 2 Q 3 Q 4 Q 1 Q 2 Q 3 Q 4 Q 1 Q 2 Q 3 Q 4 Q 1Q
Ice Processes Study (Section 7.6)
Existing Condition 1-D Model Development
Proposed Condition 1-D Model Development
Intensive Site Models
Geomorphology Study (Section 6.5)
Integration with & Support of Interpreting Fluv. Geomorph. Modeling Results
Fluvial Geomorphology (Section 6.6)
Coordination w/ Other Studies on Modeling Needs Including Focus Areas ●
Coordinate with Other Studies on Processes Modeled
Perform 2-D Modeling of Existing Conditions
Perform 1-D Modeling of Alternative Scenarios
Perform 2- Modeling of Alternative Scenarios
Post Process and Provide Model Results to Other Studies
Interpretation of Channel Change and Integration with Other Studies
Groundwater Study (Section 7.5)
Riparian Vegetation Dependency on SW/GW Interactions
Fish and Aquatics Instream Flow Study (Section 8.5)
Hydraulic Flow Routing (Section 8.5.4.3)
Distribute final mainstem (open-water) routing model to TWG for review ▲
Use final mainstem (open-water) routing model for scenario evaluations
Hydrologic Data Analysis (Section 8.5.4.4)
TWG meeting to review complete hydrologic record ▲
Use hydrologic record for scenario evaluations
RIPARIAN PHYSICAL PROCESS MODELING
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 10 March 2013
Legend:
─ Planned Activity
- - - Follow-up activity (as needed)
● Technical Memorandum or Interim Product
Δ Initial Study Report
▲ Updated Study Report
RIPARIAN PHYSICAL PROCESS MODELING
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 11 March 2013
Table 2. Information and products required by the Riparian IFS Study from other studies.
Source of Product or Information Information or Product to be Provided Timing
Information or Products Required for: Recruitment Box Model of Seed Dispersal Timing and Flood Regime
IFS Flow Routing (Section 8.5) Flow Modeling (Frequency, magnitude, duration, and
seasonal timing)
Q4-13
Q4-14 Geomorphology Study (Section 6.5)
Information or Products Required for: Seedling Establishment and Recruitment Study
Fluvial Geomorphology Study (Section 6.6) Groundwater, surface water, and sediment regime
characteristics of seedling sites
Q4-14
Groundwater (Section 7.5) Q4-14
Ice Processes (Section 7.6) Ice influence vertical and horizontal zones Q4-14
Information or Products Required for: River Ice and Floodplain Processes Study
Ice Processes (Section 7.6) Ice Process modeling results – Spatial location of ice,
vertical extent of ice, and potential ice dam locations Q4-13
Q4-14
Information or Products Required for: Role of Erosion and Sediment Deposition in Floodplain Processes
Fluvial Geomorphology Study (Section 6.6)
Historic channel migration rates, floodplain vegetation
disturbance or turnover rate Q4-13
Flood frequency, magnitude, duration, and timing Q4-13
Sediment transport and depositional spatial model Q4-14
IFS Flow Routing (Section 8.5) Study Area-wide flood frequency, magnitude, duration,
and timing Q4-13
Q4-14
Riparian Botanical Survey (Section 11.6) Sediment and soils stratigraphic description, strata
management and floodplain sediment dating Q4-13
Q4-14
Information or Products Required for: Groundwater and Surface Water Maintenance Hydroregime
Groundwater (Section 7.5)
GW/SW interaction modeling seasonal statics
including frequency, timing, and duration of water
levels.
Q3-13
through
Q4-14
RIPARIAN PHYSICAL PROCESS MODELING
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 12 March 2013
Table 3. Information and products the Riparian IFS Study will provide to other studies.
Study the Product or Information
is Provided to Information or Product to be Provided Timing
Groundwater Study (Section 6.5) Evapotranspiration model data for incorporation into MOD-FLOW Q4-13 & Q4-14
Riparian Botanical Survey (Section
11.6)
Dendrological studies results: ITU sample plot tree ages, and
shrub and tree composition and abundance measurements Q4-13 & Q4-14
RIPARIAN PHYSICAL PROCESS MODELING
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 13 March 2013
Table 4. Primary output variables for which values are taken directly from the 1 -D and 2-D mobile-boundary models and relevance to other studies.
Variable Description of Model Output Spatial Resolution Relevance to Other Studies
1-D mobile-boundary model
Water-surface profiles Steady-state water-surface profiles for all discharges Cross section Geomorphology
Cross-sectionally averaged hydraulic
conditions
Flow depth, velocity, bed shear stress, channel top
width Cross section FA-IFS, R-IFS, Geomorphology
Bed material load transport rates Transport rates by grain size fraction Cross section Geomorphology
Bed material (i.e., substrate) gradations Change in surface layer bed gradations by cross
section over time (0, 25, 50 years) Cross section FA-IFS, Geomorphology
Bed elevation Changes in bed elevation with time Cross section, longitudinal profile FA-IFS, R-IFS, Geomorphology,
GW
2-D mobile-boundary model
Water-surface elevations Steady and unsteady water-surface elevations Grid element FA-IFS, R-IFS, Geomorphology,
GW
Depth-averaged hydraulic conditions Flow depth, velocity (magnitude and direction), bed
shear stress Grid element FA-IFS, R-IFS, Geomorphology,
GW
Flow distribution among multiple channels
(including side channels)
Discharge in each branch (including side channels)
over range of flows; changes associated with bed
evolution model results
Channel width FA-IFS, R-IFS, Geomorphology,
GW
Bed material load transport rates Transport rates by grain size fraction, including supply
to and transport through side channels Grid element FA-IFS, R-IFS, Geomorphology,
GW
Bed material (i.e., substrate) gradations Change in substrate gradations by grid element over
time, including side channels and side sloughs Grid element FA-IFS, R-IFS, Geomorphology,
GW
Bed elevation
Changes in bed elevation with time, including side
channels and side sloughs. Evolution of mouths and
spawning areas of particular interest
Grid element FA-IFS, R-IFS, Geomorphology,
GW
Breaching flows Magnitude, frequency and duration of flows overtopping
control at the head of side channels Grid element →side channel width FA-IFS, Geomorphology
RIPARIAN PHYSICAL PROCESS MODELING
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 14 March 2013
Table 5. Key variables needed for the impact assessments for which results are obtained through additional analysis of predictions taken directly from the 1-D and 2-D
mobile-boundary models.
Variable Description Spatial Resolution Relevance to Other Studies
1-D mobile-boundary model
Wash load transport rates Correlations between wash load transport rates and
discharge Gage locations WQ, R-IFS
Overbank sedimentation rates Rate of sediment delivery into overbanks and vertical
accretion rates Reach-averaged R-IFS, Geomorphology
Breaching flows Magnitude, frequency and duration of flows overtopping
control at the head of side channels Site R-IFS, Geomorphology
Side channel connectivity Frequency, duration and inundation extent of backwater
flows into side channels Site R-IFS
Bed Material Motion Thresholds (aka
Incipient Motion Analysis)
Frequency and duration of flows sufficient to cause
general mobilization of bed material
Cross section and/or reach-
averaged FA-IFS, Geomorphology
Bed material transport capacity rating
curves
Bed material transport capacity (total and by-size
fraction) as a function of discharge
Cross section and/or reach-
averaged Geomorphology
Effective Discharge Magnitude and frequency of flows that transport the
most sediment over defined period of time Reach-averaged Geomorphology
Bank erosion rates Estimated rate of erosion into main and side channel
banks
Cross section and/or reach-
averaged R-IFS, Geomorphology
LWD recruitment Quantities of LWD delivered to mainstem and side
channels due to bank erosion Reach R-IFS, Geomorphology
Deposition rates at tributary mouths Evolution of tributary mouth fans/bars over time Geomorphology unit FA-IFS, Geomorphology
Hydraulic conditions at tributary mouths Potential effect of changes in tributary mouths and
effects on fish passage into tributaries Geomorphology unit FA-IFS, Geomorphology
2-D mobile-boundary model
Weighted-useable-area versus discharge
curves
Hydraulic conditions (velocity, depth, substrate size)
provided to FA-IFS for WUA estimates Grid element→ Habitat unit FA-IFS, Geomorphology
Overbank sedimentation rates Rate of sediment delivery into overbanks and vertical
accretion rates Grid element R-IFS, Geomorphology
Bed Material Motion Thresholds (aka
Incipient Motion Analysis)
Frequency and duration of flows sufficient to cause
general mobilization of bed material Grid element→ Habitat unit FA-IFS, Geomorphology
Bank erosion rates Changes in bank shear stress and bank energy index
(BEI) Model reach R-IFS, Geomorphology
Changes in side channel, side slough and
upland slough geometry Evolution of channel width and depth Grid element →side channel width FA-IFS, R-IFS,
Geomorphology
Fine sediment interactions in spawning
areas
Potential for infiltration and flushing of fines from
spawning substrate, including side channels and side
sloughs
Grid element→ Habitat unit FA-IFS, R-IFS,
Geomorphology
RIPARIAN PHYSICAL PROCESS MODELING
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 15 March 2013
Variable Description Spatial Resolution Relevance to Other Studies
LWD recruitment Changes in bank erosion rates that could affect LWD
recruitment Grid element FA-IFS, R-IFS,
Geomorphology
RIPARIAN PHYSICAL PROCESS MODELING
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 16 March 2013
5. FIGURES
RIPARIAN PHYSICAL PROCESS MODELING
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 17 March 2013
Figure 1. Susitna River Project Area.
RIPARIAN PHYSICAL PROCESS MODELING
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 18 March 2013
Figure 2. Study interdependencies for Riparian Instream Flow Study (Source: RSP Section 8.6).
IFS F & A 8.5
IFS Riparian 8.6
Groundwater
7.5
Ice Processes
7.6
Riparian
Botanical
11.6
Fluvial
Geomorphology
6.6
Groundwater 7.5 Ice Processes
7.6
Project Area Riparian
Vegetation & Soils
Mapping &
Quantitative
Description
(Q 4, 2013; Q4 2014)
Site Selection
Riparian Process Domain
Modeling Needs
Field Data Sharing
(Q 4-2012, Q1-2013)
Groundwater / Surface
Water Interaction
Study Model
•Groundwater Depth
•Seasonal Statistics
•Project operational
effects
(Q3-4, 2014)
Geomorphic Processes
Sediment Supply Regime
Hist. Channel Change
Flood Freq. & Flow Duration
(Q4, 2013; Q3-4, 2014)
Ice dam regime and river
network location
Ice / floodplain interactions
(Q3-4, 2014)
STUDY INTERDEPENDENCIES FOR RIPARIAN INSTREAM FLOW STUDY SECTION 8.6
Vegetation
Sampling,
Dendrochronology,
Seed Dispersal,
Seedling
Recruitment
(Q2-4, 2013; Q2-4,
2014)
Scaling Model
−from Reach to
Riparian Process
Domain
Geomorphology
6.0
Potential Changes in Floodplain
Vegetation Habitats & Plant
Community Succession:
-Relative Spatial Distribution
-Types of projected change
(Q4, 2013; Q1, 2015)
Vegetation Flow-
Response & Physical
Process Regime
Modeling (Flooding,
Sediment, Ice,
Channel, Climate)
Ice Processes
7.6
River
Productivity
9.8
Project Operational
Flow Design
Sediment Dating
(dendrochronology &
Isotopic/Radiogenic)
(Q4, 2013; Q4 2014)
Dendrochronology
(tree ice scar)
(Q4, 2013; Q4 2014)
Seed Dispersal,
Hydrology,
Climate
Synchrony Model
Riparian
Botanical
11.6
Wildlife
10.0
Geomorphology
Large Woody
Debris 6.5.4.9
RIPARIAN PHYSICAL PROCESS MODELING
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 19 March 2013
Figure 3. Floodplain Vegetation Study Synthesis, Focus Area to Riparian Process Domain Scaling & Project Operations Effects Modeling (Source: RSP Section 8.6.3.7).
Riparian
Botanical
11.6
Fluvial
Geomorphology
6.6
Riparian Process
Domain Map
8.6.3.2
Ice Processes
7.6
1.Study Area
floodplain
vegetation
mapping.
2.Forest
succession
models
(Q 4 2014)
Project riparian
process domain map
(Q4 2013)
Geomorphic Processes
Sediment Supply Regime
Hist. Channel Change
Flood Freq. & Flow Duration
(Q4 2014)
Ice process modeling
1.existing conditions
2.project operations
scenarios
(Q4 2014)
FLOODPLAIN VEGETATION STUDY SYNTHESIS, FOCUS AREA TO RIPARIAN PROCESS
DOMAIN SCALING & PROJECT OPERATIONS EFFECTS MODELING 8.6.3.7
Spatially explicit
mapping of
modeled
Operations
scenarios floodplain
vegetation effects.
Q1-2 2015
Floodplain
erosion and
sediment
deposition
vegetation
model
8.6.3.5
1.Ecological model of
Susitna River floodplain
vegetation establishment
and recruitment.
2.Floodplain vegetation
Operations effects
simulation model.
Q1-2 2015
Seed Dispersal,
hydrology
climate model
8.6.3.3
Project
Operational Flow
Design
Sediment
transport &
deposition rates
(Q4 2014)
Seed dispersal
timing and flow
regime
requirements
(Q4 2014)
Seedling
establishment
study
8.6.3.3.2
Seedling
establishment
flow & sediment
regimes
requirements
(Q4 2014)
Floodplain ice
process
interaction
zones
(Q4 2014)
River ice effects
floodplain
vegetation study
8.6.3.4
Floodplain plant
community GW/SW
regime
requirements
(Q4 2014)
Floodplain
vegetation
GW/SW
interaction
model 8.6.3.6
RIPARIAN PHYSICAL PROCESS MODELING
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 20 March 2013
Figure 4. Seed Dispersal, Hydrology and Climate Synchrony (Source: RSP Study 8.6.3.3.1).
Flow Routing 6.5
Historic peak flow
hydrograph analyses
(Q2-Q4, 2014)
SEED DISPERSAL, HYDROLOGY AND CLIMATE SYNCHRONY STUDY 8.6.3.3.1
Model of Poplar and willow seed
dispersal, hydrology and climate
(Q4 2014)
Riparian IFS
Scaling &
Project
Effects
Modeling
8.6.3.7
Project
Operation
Design
1. Seed dispersal field
surveys (Q2 2013; Q2
2014).
2. Hydrologic analyses,
3. Climate modeling.
RIPARIAN PHYSICAL PROCESS MODELING
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 21 March 2013
Figure 5. The riparian “Recruitment Box Model” describing seasonal flow pattern, associated river stage (elevation), and
flow ramping necessary for successful cottonwood and willow seedling establishment (from Amlin and R ood 2002; Rood
et al., 2005). Cottonwood species (Populus deltoides), willow species (Salix exigua). Stage hydrograph and seed release
timing will vary by region, watershed, and plant species.
RIPARIAN PHYSICAL PROCESS MODELING
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 22 March 2013
Figure 6. Cottonwood (Populus) life history stages: seed dispersal and germination, sapling to tree establishment. Cottonwo od typically germinates on newly created
bare mineral soils associate with lateral active channel margins and gravel bars. Note proximity of summer baseflow and floo dplain water table (Braatne et al. 1996).
RIPARIAN PHYSICAL PROCESS MODELING
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 23 March 2013
Figure 7. River Ice-Floodplain Vegetation Establishment and Recruitment (Source: RSP Section 8.6.3.4).
Riparian
Botanical
11.6
Botanical survey mapping
of:
1.tree ice-scars,
2.shrub scars,
3.floodplain ice gravel
and soil shearing ,
4.plant community types.
(Q 4, 2013; Q4 2014)
1.Seasonal ice formation and
break-up videography (Q4
2012, Q1-2, 4 2013; Q1-2, 4
2014)
2.Summary of 1980’s ice process
studies.
3.Ice process modeling results
(Q4 2014)
RIVER ICE− FLOODPLAIN VEGETATION ESTABLISHMENT AND RECRUITMENT 8.6.3.4
1.Using ice process domain map,
develop quantitative study
comparing ice influenced and non-
ice-influenced floodplain plant
community establishment and
recruitment.
2.Characterize role, and degree of
influence ,of ice processes in Susitna
River floodplain vegetation.
1.Vegetation study design (Q2 2013).
2.Characterization of ice process effects on
floodplain vegetation (Q4 2014).
Riparian IFS
8.6.3.2,
8.6.3.3
Riparian
Botanical
11.6
Ice Processes 7.6
Ice Processes 7.6
1.Tree ice scar and gravel
deposit mapping (Q3-4
2012; Q1-3 2013; Q1-3
2014).
2.Interview local Susitna
residents about ice dam
locations (Q1-2 2013).
3.Develop iterative map of
river ice floodplain
vegetation interaction
domains (Q2 & Q4 2013;
Q4 2014).
Riparian IFS
Scaling &
Project
Effects
Modeling
8.6.3.7
RIPARIAN PHYSICAL PROCESS MODELING
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 24 March 2013
Figure 8. Relationship of ice observations to other studies (Source: RSP Section 7.6.11) .
RIPARIAN PHYSICAL PROCESS MODELING
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 25 March 2013
Figure 9. Floodplain Erosion, Sediment Deposition & Floodplain Vegetation Study (Source: RSP Section 8.6.3.5).
Riparian
Botanical
11.6
Fluvial
Geomorphology
6.6
1.Floodplain sediment &
stratigraphy descriptions.
2.Floodplain soils analyses.
3.Floodplain isotopic
sediment dating.
4.Plant community mapping.
(Q 4, 2013; Q4 2014)
1.Focus Areas (FA) channel migration
rates.
2.FA’s floodplain disturbance rates.
3.FA’s flood frequency, magnitude,
duration, timing hydrograph and
modeling analyses.
4.2-D sediment transport and
floodplain sediment deposition
modeling.
(Q3-4, 2013; Q3-4 2014)
Project Area wide 1-D
hydraulic modeling of
historic flood frequency,
magnitude, duration and
timing (Q4 2013).
FLOODPLAIN EROSION, SEDIMENT DEPOSITION & FLOODPLAIN VEGETATION STUDY 8.6.3.5
1.FA sediment deposition rate
characterization and mapping.
2.FA sediment and soil development
rate analyses.
3.Floodplain and floodplain vegetation
development conceptual model.
(Q4 2014)
Riparian
Botanical
11.6
Fluvial
Geomorphology
6.6
Flow Routing
Modeling IFS 8.5
1.Dendrochronologic studies (tree /
floodplain dating) (Q4 2013; Q4
2014).
2.Floodplain sediment deposition
rate analyses (Q4 2013; Q4
2014).
3.Analyses of floodplain plant
community types & sediment
characteristics. (Q4 2013; Q4
2014)
Riparian IFS
Scaling &
Project
Effects
Modeling
8.6.3.7
RIPARIAN PHYSICAL PROCESS MODELING
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 26 March 2013
Figure 10. Study interdependencies for the Fluvial Geomorphology Modeling Study (Source: RSP Section 6.6).
RIPARIAN PHYSICAL PROCESS MODELING
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 27 March 2013
Figure 11. Floodplain Vegetation Groundwater & Surface Water Study (Source: RSP Section 8.6.3.6).
Riparian
Botanical
11.6
Fluvial
Geomorphology
6.6
Groundwater 7.5
Focus Area
Vegetation mapping & survey
sampling
Soils mapping &
characterization
(Q 4, 2013; Q4 2014)
Groundwater / Surface Water
Interaction Study Model
•Measure and model
frequency, magnitude,
duration & timing of surface &
groundwater flux
•Model project operational
GW/SW effects
(Q3-4, 2014)
Focus Area
Surface water flow regime
modeling
•Stage/discharge regime
•1D/2D model
(Q4, 2013; Q3-4, 2014)
FLOODPLAIN VEGETATION GROUNDWATER & SURFACE WATER STUDY 8.6.3.6
Probabilistic floodplain vegetation
GW/SW regime response curves (Q4
2013; Q4 2014)
Analysis of floodplain vegetation
water sources (Q4 2013, Q4 2014)
Vegetation flow-
response & GW/SW
modeling .
Isotopic analysis of
floodplain vegetation
water sources
(Q4, 2013; Q2-4 2014;
Q1 2015)
Riparian IFS
Scaling &
Operations
Modeling
8.6.3.7
RIPARIAN PHYSICAL PROCESS MODELING
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 28 March 2013
Figure 12. Study interdependencies for the Groundwater Study (Source: RSP Section 7.5).
Geology and Soils (4)
IFS Fish (8.5)
IFS Riparian (8.6)
Fluvial Geomorphology (6.6)
Ice Processes (7.6)
Fish Studies (9)
ADNR/GINA
Mapping Information
Ice Processes (7.6)
Water Quality (5.0)
Geologic and Terrain Mapping
Layers ((Q1-13)
Background Information
(Q1-13)
Geologic Data
Geotechnical Data
Ice and IFS Data
(Q2-Q4-13)
Winter Aerial Surveys
Water Quality
( Q2-Q3-13, Q1-14)
STUDY INTERDEPENDENCIES FOR GROUNDWATER STUDY
Existing Data
Synthesis
Geohydrologic Process-
Domains and Terrain
Upwelling/ Springs
Broad-Scale Mapping
All Studies
Groundwater Hydrology and
Upwelling Evaluations
(Q1-14/Q4-14)
Draft Annotated Bibliography
(Q2-13)
Annotated Bibliography
(Q4-13)
Watana
Dam/Reservoir
All Studies
Groundwater Evaluation
Potential Effects of Construction
Potential Effects of Operations (Q1-
14/Q4-14)
Geology and Soils (4)
Fluvial Geomorphology (6.6)
Ice Processes (7.6)
IFS Fish (8.5)
IFS Fish (8.5)
IFS Riparian (8.6)
Draft Process Domain
Mapping (Q2-13)
Process Domain Mapping
(Q4-13)
IFS Fish (8.5)
IFS Riparian (8.6)
RIPARIAN PHYSICAL PROCESS MODELING
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 29 March 2013
Figure 12. Study interdependencies for the Groundwater Study (Source: RSP Section 7.5) (continued).