02_BRBM_Hydrologics_Broad_Inflow_Devt_07jun2011_final

Broad River Basin Hydrologic ModelInflow DevelopmentBroad River Basin Hydrologic ModelInflow DevelopmentSteven NebikerBrian McCroddenJune 7, 2011Steven NebikerBrian McCroddenJune 7, 2011
Project Timeline•Components–Basin schematic: 1 - 2 months (complete)–Data collection (demands and discharges, including agricultural demands): 4 - 6 months (complete)–Inflow development: 6 – 10 months (complete)–Operating rules: 3 months–Current and future demand model runs: 2 - 4 months–Documentation and training: 1 month–Expected completion date: December 2011•Model is available for preliminary drought forecasts2
Data Collection (HydroLogics) •Reservoirs–Elevation-storage-area curve and operating rules–Historic elevation/release data when available•Streamflow•Precipitation/evaporation–Use stations nearest the reservoirs of interest•Drought plans•Interconnections3
Data Collection (Moffatt & Nichol) 4
Inflow Development 5
Unimpairment•Unimpaired inflows necessary for testing impacts of alternative operating policies, facilities, and demand levels•Impairments include water withdrawals/discharges and reservoir regulation (including net evaporation)•Goal: Force inflows to match monthly unimpaired gage flows, meaning measurement error is embedded in impairments and not gage flows–USGS gage data is treated as ground truth6
Geographic Scope of Model7
Upper Basin8
Middle / Lower Basin9
Gages Used10USGS Number Description Period of RecordDrainage Area (sq. mi.)Basin Gages02148500 BROAD RIVER NEAR CHIMNEY ROCK, NC 04/1927 - 09/195897 02149000 COVE CREEK NEAR LAKE LURE, NC01/1951 - present79 02150495 SECOND BROAD RIVER NEAR LOGAN, NC 10/1998 - present86.2 02151000 SECOND BROAD RIVER AT CLIFFSIDE, NC 07/1925 - 12/1996220 02151500 BROAD RIVER NEAR BOILING SPRINGS, NC 07/1925 - present875 02152100 FIRST BROAD RIVER NEAR CASAR, NC 03/1959 - present60.5 02152500 FIRST BROAD RIVER NEAR LAWNDALE, NC 03/1940 - 09/1971200 02153500 BROAD RIVER NEAR GAFFNEY, NC12/1938 - 09/1971, 06/1986 - 09/19901,490 Reference gages outside of the basin02138500 LINVILLE RIVER NEAR NEBO, NC07/1922 - present66.702143000 HENRY FORK NEAR HENRY RIVER, NC08/1925 - present83.202143040 JACOB FORK AT RAMSEY, NC10/1961 - present25.702143500 INDIAN CREEK NEAR LABORATORY, NC09/1951 - present69.2
01234567891011121930 1935 1940 1945 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 2010Gage Reference NumberTimeline for Gage DataGage TimelineJacobHenryNeboGaffney1stBroad Lawndale1stBroad CasarBoiling Springs2ndBroad Cliffside2ndBroad LoganCove CreekBroad - Chimney11Indian
Gage MapGage has significant impairment(2007 average flow and monthly minimum flow)Gage has little or no impairmentBroad R. Chimney RockGage has moderate impairmentCove Creek (67cfs, 15 cfs)2ndBroad CliffsideBroad R. Boiling Springs(722 cfs, 187cfs)Broad R. Gaffney2ndBroad Logan(64 cfs, 12cfs)1stBroad Casar (46 cfs, 11 cfs)1stBroad Lawndale12
Developing Inflow Records •Reservoirs–Use unimpaired stream gages immediately upstream–Otherwise, use unimpaired reference gages•Other nodes (e.g., stream gaging sites)–Adjust inflows for upstream impairments13
Developing Inflow Records (cont’d.)•Inflow records modified to eliminate negatives caused by time of travel issues and errors in impairments•Fill in missing inflow records by correlating with unimpaired inflows at other nodes–USGS Fillin program computes correlations on a monthly basis–Filled-in records must be scaled to ensure that actual unimpaired flow at downstream points is preserved•Monthly flows/gains disaggregated to daily flows using local unimpaired gage to preserve natural variation–Impairment data is mostly monthly and can therefore cause noise on a daily basis–Reservoir operations on the river impact daily flows but not monthly averages–Goal: to build daily flows whose variation is representative of history while preserving monthly gage flows as ground truth14
Spreadsheet Showing Gage Unimpairment 15
Monthly Impairments at Boiling Springs (2008)16051015202530Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov DecAverage Monthly Flow (cfs)Net WDAg. WD
Monthly Impairments at Boiling Springs (2008)1705010015020025030035040045050055060065070075080085090095010001050110011501200Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov DecAverage Monthly Flow (cfs)Net WDAg. WDGage Flow
Boiling Springs Flows18
Boiling Springs Flows19
Gaston Shoals Flows20
Gaston Shoals Flows21