AWWA SYM53625

The Swift Creek Reservoir is a 1600-acre, 4.6 billion gallon impoundment inChesterfield County, Virginia, that supplies the Swift Creek Water TreatmentPlant, a source of potable water for approximately 95,000 of the county's 256,000public water supply customers. The reservoir also serves as an aesthetic andrecreational resource for approximately 20,000 residents of communities along itsshoreline and within its direct drainage areas. Currently 75% of the reservoir'swatershed is undeveloped; however, planned expansion of housing into itswatershed has raised concerns about the future viability of the reservoir's waterquality. In an effort to determine the extent to which best availabletechnologies will need to be applied to watershed discharges in order to maintainacceptable reservoir water quality, the Swift Creek Water Plant Laboratory hasdeveloped, over the past six years with consultants assistance and citizensguidance, a reservoir and watershed monitoring program to establish a baselineagainst which future water quality changes may be gauged and responded toappropriately. Specifically, the water budget, nutrient loads, and general waterquality of the nine reservoir sub-basins and the reservoir have beencharacterized. Swift Creek Reservoir has a median depth at full pool elevation of9.0 feet and is supplied by nine major tributaries, only one of which is a trueperennial stream. In the watershed, automated samplers capable of obtainingflow-weighted composite samples have been placed on these tributaries and at tworepresentative direct runoff sites immediately adjacent to the reservoir.Continuous five minute stage data is obtained through the use of ISCO 3200 seriesBubble Flowmeters linked to the samplers at the tributaries and by the use ofISCO 6700 series Portable Samplers with a model 730 Bubble Flow Module at thedirect runoff culverts. Stage data is downloaded monthly and compiled usingFLOWLINK 2.14 and FLOWLINK 3.0 software. Stage data is subsequently merged toform a continuous record for each year and is edited for errors associated withfouling, drift, and data gaps. Includes 11 references, table, figures.