HomeMy WebLinkAboutBattle Creek Diversion Project Presentation - Jul 2013 - REF Grant 7040003Project Area Watershed Map -07/22/13DIVERSION
Project Features – 07/22/13
•Battle Creek Diversion intercepts water from West Fork Upper Battle Creek •Water is conveyed by canal from West Fork Diversion to Bradley Lake •Surface runoff from area upslope from the canal is intercepted as sheet flow from storm precipitation and snow melt •West and East Branches of Middle Fork Upper Battle Creek are intercepted; these are intermittent very steep channels in bedrock Diversion, Head Works and Canal
Battle Creek Diversion Features •Design of the Physical features of the Battle Creek Diversion is 95% complete.•Location of Diversion is unchanged except as affected by structural details.•Canal design has developed to take better advantage of the geologic conditions along the alignment.•Terminus of the canal near Bradley Lake has been revised to take advantage of geology at the Upper Battle Creek Diversion and provide better interception of the UBC flows by new canal.
Diversion Site 06/29/12 Battle Glacier
Diversion Site on West Fork Upper Battle Creek, View Upstream
Canal Alignment Note brushed line for topo survey
Middle Fork Upper Battle Creek
Hydraulics of Battle Creek Diversion •Hydraulic Design takes into account the Probable Maximum Flow that statistically will occur during the project life.•The Inflow Design Flood and Spillway Design Flood are equal and are 1,800 cfs at the diversion. Probable Maximum Flood is 4,000 cfs•The 100-year recurrence flood is 1,580 cfs at the diversion•Control of diverted and bypassed water is by gates at diversion dam – head works.
Typical Canal Cross-section Showing Depth and Velocity of Flow
Daily Average Inflow at Diversion by Month
Canal Terminus at Bradley Lake•Canal intercepts the Existing Upper Battle Creek Diversion flows (East Fork Upper Battle Creek) •Terminus of extended canal approximately 1,200 feet East of original planned terminus at base of Upper Battle Creek Falls (moved terminus because of unfavorable geology for canal terminal structure •Canal discharges into existing channel in rock that is outlet for the existing Upper Battle Creek Diversion
Canal Terminus Revised Location Initially Planned Terminus Location Revised Terminus Location
Existing Upper Battle Creek Diversion to Bradley Lake - Springtime
Existing Upper Battle Creek Diversion to Bradley Lake - Springtime
Existing Upper Battle Creek Diversion Outlet Natural Channel to Bradley Lake
Existing Upper Battle Creek Diversion Outlet to Bradley Lake
Battle Creek Diversion Access and Safety Features •Ladders and grab bars provided along canal for personnel access and safety •Maintenance access ramps provided at two locations to facilitate access for equipment •Wildlife access and escape ramps provided at approximately 12 locations on left side of canal channel and 4 locations on right side of canal (where animals can cross the canal using ramps)
Canal Maintenance Access Ramp
Canal Wildlife Access and Escape Ramp
Table 3-1 - Battle Creek Diversion Flood Frequency Analysis Results Total contributing drainage area above location7.4 mi27.6 mi27.8 mi28.2 mi29.2 mi2 Diversion Structure cfsUpper Canal cfsUpper Canal Transition cfsLower Canal cfsLower Canal Transition cfsDrainage Area Unit Runoff cfs/sq miFlood Recurrence Interval2-year580 600 610 650 720 795-year840 850 880 930 1,030 11310-year1,010 1,030 1,060 1,110 1,250 13625-year1,230 1,250 1,290 1,360 1,530 16650-year1,410 1,430 1,470 1,560 1,740 190100-year1,580 1,610 1,650 1,740 1,950 213
Table 2-1 - Diversion Bypass and Canal Capacity vs Flood Flow Description Flow in CFSWater Surface Elevation of Headwater Pool Primary Bypass Only Primary Bypass plus 3X8 SluicePrimary Bypass plus Canal3X8 Sluice plus CanalCanal only2 feet of freeboard WS @ EL 17041,351 1,798 2,130 1,226 779Zero feet of Freeboard, WS @ EL 17061,757 2,235 2,787 1,508 1,03010-year recurrence flood1,010 1,010 1,010 1,010 1,010100-year recurrence flood1,580 1,580 1,580 1,580 1,580Factor of safety for passing 100-year event, zero freeboard1.11 1.41 1.76 0.95 0.65 IDF: 45% of Probable Maximum Flow1,800 1,800 1,800 1,800 1,800“Factor of safety” for IDF event, zero freeboard0.98 1.24 1.55 0.84 0.58Approx WS elevation to pass IDF event, feet1708.1 1706.11703.0N/AN/A