Water Resources Professional Project Reports

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Many of the lakes and reservoirs in the world are adversely affected by eutrophication. In order to counter this trend, the U.S. Environmental Protection Agency (USEP A) had developed numeric nutrient criteria for use by the States and Tribes. The USEP A has based their criteria on Level III ecoregions and their aggregated ecoregions. This project seeks to determine the validity of using these USEP A recommendations in the State of New Mexico to replace the State's current narrative nutrient criteria. This project will also offer nutrient criteria recommendations for four criteria variables: total nitrogen, total phosphorus, Secchi depth, and chlorophyll-a, based on three other lake classification schemes, the first one based on surface area, the second on elevation, and the third on surface area to drainage area ratio. The water bodies of interest in this study are the mainstem reservoirs of New Mexico with surface areas greater than 1,000 acres. Using the Carlson trophic state index as a guide, this study finds that the Level III ecoregion approach to lake classification has the most potential to preserve, and possibly improve, the current trophic states of the reservoirs in New Mexico. This result and the recommendations for future work will be used by the State of New Mexico as a starting point for the development of numeric nutrient criteria.

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Eutrophication, Watershed management practices, New Mexico reservoirs, Nitrogen concentrations, Phosphorus, Phytoplankton, Secchi depth, State of New Mexico Standards for Interstate and Intrastate Surface Waters


A Professional Project Report submitted in Partial Fulfillment of the Requirements for the Degree of Master of Water Resources, Hydroscience Concentration, Water Resources Program, The University of New Mexico Albuquerque, New Mexico, August 2005.