WALLENPAUPACK. Lake Wallenpaupack Operations during the April 2005 Flood

Transcription

1 LAKE WALLENPAUPACK Lake Wallepaupack Operatios durig the April 2005 Flood

2 Lake Performace Summary March-April Storm Evet LAKE WALLENPAUPACK Over 14 BG of water stored betwee March 28 ad April 3 icludig approximately 6.7 BG of water stored betwee April 2 ad 3. Maximum water release of 8,000 cfs (6,300 cfs spill ad 1,700 cfs plat release) - Approximately 13,000 cfs less tha the peak iflow ito the lake. Effect o Flood Levels. Lackawaxe River - Approximately 4.5 foot reductio to flood stage. Delaware River - slight reductio to flood stage at Port Jervis ad o measurable effect at poits further south alog the river.

3 Project costructed i Square Mile watershed ( Approx. 6.5% of the watershed at Port Jervis) 5700 Acre Lake at Normal pool level miles log Approx. 38 BG of water stored betwee El 1165 ad ormal maximum El 1187 Approximately 5.5 BG of flood storage betwee El 1187 ad El 1190 (Poit at which spills must begi) Approximately19.5 BG of flood storage space above El 1190 THE LAKE

4 THE MAIN DAM & PIPELINE Dam Cocrete o-overflow ad a adjacet earthe embakmet. Cocrete sectios Top - El 1200 Earthe Dam Top - El 1203 Combied legth 1272 feet 135 Spillway sectio with 2 roller gates (Top El = 1190) Desiged for PMF hydrology - relies o spills to esure dam safety Pipelie 3.5 mile, 14 foot diameter, 1700 cfs capacity --All releases, except spills, are diverted through the pipelie

5 Surge Tak LAKE WALLENPAUPACK Pestocks Powerhouse THE SURGE TANK & GENERATING PLANT

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7 Project Operatios - Lake Maagemet LAKE WALLENPAUPACK Lake is maaged to mothly lake level targets (rule curve - historically variable) for multiple ad balaced objectives Hydroelectric Power Geeratio Peakig - System Reliability Lake & Dowstream Recreatio Fisheries Maagemet Delaware Basi Drought Assistace Seasoal Flood Cotrol

8 LAKE WALLENPAUPACK FIRST OF MONTH NORMAL LAKE LEVEL TARGETS Lake Level (Local Datum) Witer Geeratio Support of Summer Recreatio, Hydropower Operatios, Drought ad Fishery Objectives Additioal storage available to capture sprig ru-off Additioal storage available durig Tropical storm seaso JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC Moth

9 Lake Target Elevatios debated ad established or recofirmed durig three years of relicesig studies ( ) ad supported by a cosesus of federal, state ad local stakeholders. Desiged to support multiple-purposes ad eeds. All uses ad eeds were equally cosidered ( Balaced Operatios). Greater Use for oe purpose ( Ex: flood cotrol) will impact or elimiate other importat uses.

10 FLOOD OPERATIONS

11 Project Spills LAKE WALLENPAUPACK Desig Spill uder Probable Maximum Flood (PMF) = 80,000 cfs Flood of Record (1955) = 24,000 cfs Flood Isurace Study (FIS) 100 year flood = 12,000 cfs assumed O average spills have occurred approximately oce every te years i 79 year project history PPL operates where feasible ot to spill (Ex: Hurricae Iva - No spill)

12 MARCH - APRIL 2005 Evet

13 Heavy March sowfall dramatically icreased sowpack coditios i the Lake Wallepaupack watershed

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16 Lake Wallepaupack Elevatio March 27 to April Spills iitiated whe lake reached El ad was cotiuig to rise (Still Raiig) Lake Elevatio Lake Level exceeded ormal by 3 PM o Saturday April 2d BG Stored Approx. 14 BG of water stored Elapsed Time i Hours

17 Lake Wallepaupack Routig of March-April 2005 Flood Est. Peak Iflow - Approx 21,000 cfs Maximum release was less tha 40% of peak iflow to the lake Flow (cfs) Peak Outflow - 8,000 cfs Spill - 6,300 cfs Plat - 1,700 cfs 5000 Maximum plat release iitiated Friday morig 4/ Time (Hours) Total Project Release (CFS) Estimated 4-HR Avg Project Iflow (CFS)

18 Hawley Gage Data Gage Height, feet Estimated Gage Height Abset Wallepaupack feet Effect of Spill - Approximately 2 Feet Net Effect of Wallepaupack = Approx. 4.5 foot Stage reductio Gage Height (Feet) Start of Lake Wallepaupack Spill Plat - 1,700 cfs Flow (cfs) Elapsed Time (Hours) Peak Iflow - Approx 21,000 cfs Maximum plat release iitiated Friday morig 4/1 Peak Outflow - 8,000 cfs Spill - 6,300 cfs Time (Hours)

19 Port Jervis Gage Data Gage height, feet Gage height (Feet) Difficult to separate effects of Wallepaupack from other basi reservoirs, however Wallepaupack Spill appears to have slightly icreased Delaware River Stage at Port Jervis (speculative). Cumulative Wallepaupack storage reduced Port Jervis flood stage Start of Lake Wallepaupack Spill Elapsed Time (Hours) At poits below Port Jervis the effects of Lake Wallepaupack o Delaware River flood stages are idiscerible.

20 Lake Performace Summary March-April Storm Evet LAKE WALLENPAUPACK Over 14 BG of water stored betwee March 28 ad April 3 icludig approximately 6.7 BG of water stored betwee April 2 ad 3. Maximum water release of 8,000 cfs (6,300 cfs spill ad 1,700 cfs plat release) - Approximately 13,000 cfs less tha the peak iflow ito the lake. Effect o Flood Levels. Lackawaxe River - Approximately 4.5 foot reductio to flood stage. Delaware River - slight reductio to flood stage at Port Jervis ad o measurable effect at poits further south alog the river.

21 Lessos Leared LAKE WALLENPAUPACK Public Notificatio uder our spill procedure has bee modified ad improved i cosultatio with local EMA officials. Storm forecast accuracy improvemets ad improved data availability (Ex. experimetal sowpack data) provide the opportuity for ehaced flood cotrol operatios goig forward.