Watershed Restoration and Flood Control along Steamboat Creek Using Constructed Wetlands

Abstract

Channel restoration along Steamboat Creek through revegetation and construction of wetlands has the potential to significantly improve water quality. Agricultural and stormwater runoff from the watershed feeding Steamboat Creek results in nonpoint source loadings of pollutants (e.g., nitrogen, phosphorus, and suspended solids) to the Truckee River. Steamboat Creek is also fed by geothermal hot springs as it passes through Washoe Valley. This results in high boron concentrations and increased total dissolved solids (TDS). Boron inhibits plant growth, which may have contributed to a loss of riparian vegetation along the stream channel. The loss of vegetation has resulted in bank erosion and increased total suspended solids (TSS). The combination of nutrients, TSS, boron, and TDS degrades water quality in Steamboat Creek, making it the most polluted tributary of the Truckee River. Channel revegetation will promote the uptake of nutrients, improved the stability of stream banks, and reduce erosion. A small-scale wetlands system was constructed and routinely monitored in order to quantify the effectiveness of wetlands to reduce nonpoint source pollution in Steamboat Creek. Results indicate that the system can effectively reduce nitrogen, phosphorus, and suspended solids. Typical removal efficiencies range from 65% to 99% for nitrate and nitrate, from 30% to 80% for ammonia, 20% to 60% for total phosphorus, 20% to 75% for orthophosphate, and 80% to 95% for suspended solids. Ultimately, data from this research project will be used to predict water quality improvements and develop preliminary design criteria for a large-scale wetlands system.