Evaluation of the TMDL of the East Canyon Reservior Using Remote Sensing

The objective of this paper is to determine if the implementation of the Total Maximum Daily Load (TMDL) in 2000 was successful in reducing excessive biological production in the East Canyon Reservoir using remote sensing. In this study, it was shown that data from the Landsat 5 Thematic Mapper (TM) could be used to compute the Chlorophyll-a concentration in the reservoir. A ratio of the blue (band 1) and green (Band 2) bands from the Landsat data were used to predict Chlorophyll-a concentrations. With this model 64 contour maps were produced showing the spatial distribution of the Chlorophyll-a over the East Canyon Reservoir for Spring, Summer and Fall seasons from 1984 to 2010. A power equation model using these bands was fit to the data and found to have a correlation coefficient of 0.85 when compared to in-situ Chlorophyll-a measurements. An evaluation of these data showed at Chlorophyll-a concentrations in the reservoir were increasing in both the summer and fall prior to the implementation for the TMDL, but after TMDL implementation Chlorophyll-a concentrations in the reservoir are decreasing with time. In the spring it appears that Chlorophyll-a concentrations are continuing to increase with time even after TMDL implementations. These results may indicate that the TMDL does not control some source of phosphorous loading that occurs in the spring such as loads produced from agriculture and spring run-off. The evaluation of Chlorophyll-a concentrations using satellite imagery appears to be a useful tool in the evaluation of the effects of pollution control strategies.