Presentation Poster: Chalk Creek Watershed Characterization

Chalk Creek watershed drains 2,967 acres (4.6 square miles) on the south slope of Peavine Mountain in northwest Reno, Nevada. The creek flows south via several tributaries and discharges to the Truckee River. The Cities of Reno and Sparks have monitored the watersheds that drain to the Truckee River, and identified Chalk Creek as a source of elevated total dissolved solids (TDS), total nitrogen, and total phosphorous to the Truckee River, a river with established total maximum daily loads (TMDLs) for these same constituents. The Nevada Division of Environmental Protection’s (NDEP) 2006 303d list of impaired water bodies has listed Chalk Creek for sulfate, ortho-phosphorus, TDS, and selenium. Within the watershed, the sources of these constituents of concern are unclear, as is the source of flow. Reno residents have indicated that Chalk Creek was an ephemeral stream that has become perennial.

In effort to reduce the non-point source pollution to the Truckee River, the City of Reno contracted with JBR Environmental Consultants, Inc. (JBR) to perform a watershed characterization of the Chalk Creek watershed. The goals of the watershed characterization were to identify likely flow, TDS, nutrient (nitrogen and phosphorous) sources, and evaluate potential mitigation measures to reduce TDS and nutrient loading to the Truckee River from this watershed. JBR has utilized GIS to evaluate ongoing changes to the watershed based on pervious versus impervious surfaces as related to land usage and urban growth. Spatial analyses including surface calculations using digital elevation models were performed to generate field maps showing cross-sectional views of channels within the watershed. The GIS also allowed JBR to spatially relate and manage the large amounts of water quality data compiled within the project area and helped to guide the design of a mitigation area. GIS tools for spatial analyses, topographical analyses, and data coordination have allowed the flexibility to apply a focused remediation plan.