City of Austin Performance Report 2014-15
Tons of Total Suspended Solids (TSS) Removed Annually in Drainage Areas with Publicly-Funded Structural Water Quality Controls (Tons Per Year)
Structural Water Quality Controls remove pollutants from urban stormwater. Total Suspended Solids (TSS) is the pollutant indicator used to predict the performance of the control. The measure describes the cumulative amount of TSS removed by structural water quality controls.
The calculation method is performed by using a computer model to predict the amount of pollution entering a structural control. The model then calculates the amount of pollution trapped by the control and the amount untreated. The model uses algorithms developed based on monitoring data collected by Water Quality Management staff.
FY 2014-15 Results
The FY 2014-15 goal for this measure was 784 tons of TSS removed, and the actual tons of TSS removed were 778.
Assessment of Results
Over the past five years, each water quality control pond built has increased the amount of pollution trapped by the structural controls. The amount of pollution removed is directly related to the size of the water quality control facility and the size (acreage) of the contributing drainage area. Years that show higher increases of TSS removed from the previous year indicate larger controls with larger drainage areas being built. Small increases indicate focus on small controls (like rain gardens). The results show that goals have not been met four of the five years. In 2015, the shortfall was partly due to the difficulty in predicting the start and finish of construction a year prior to scheduled pond construction. Many things can happen to delay construction, which can cause lower than projected numbers, as most of these projects are coordinated with other public improvements in parks, at schools or along roadways.
Projects that will remove an additional 7 tons of suspended solids per year are currently under construction as of the close of 2015.
For more information contact Eric Loucks, Supervising Engineer, at (512) 974-2534.