Under section 303(d) of the Clean Water Act, states must identify water segments where loads of. pollutants are violating numeric water quality standards. Consequences of misidentification are quite important. A decision that water quality is impaired initiates the total maximum daily load or TMDL planning requirement. Falsely concludin~ that a water segment is impaired results in unnecessary T...

Title of Document: THE EFFECTS OF WATER QUALITY IMPROVEMENTS ON A COMMERCIAL FISHERY: EVIDENCE FROMTHEMARYLAND BLUE CRAB FISHERY Sarah Ball, Ph.D., 2014 Directed By: Associate Professor Doug Lipton, Department of Agricultural and Resource Economics Developing and implementing total maximum daily loads (TMDLs) is a costly and controversial process. However, there are many potential benefits, suc...

The State of Minnesota, in an effort to streamline the identification of impaired waters and subsequent TMDL development, has developed a watershed approach to condition monitoring and assessment similar to other states such as Ohio and Indiana. The watershed approach uses intensive biological monitoring (fish and macroinvertebrates) to determine biologically impaired stream reaches. Follow up ...

Lake Macatawa is a hypereutrophic water body that connects with Michigan via navigation channel. Excess phosphorus (P) concentrations have resulted in Total Maximum Daily Load (TMDL) for total (TP) the lake, which has not been met. To guide land management and pollution control watershed, Soil Water Assessment Tool (SWAT) model scenarios of agricultural best practices (BMPs) were developed cons...

An indirect simulation-optimization model framework with enhanced computational efficiency and risk-based decision-making capability was developed to determine optimal total maximum daily load (TMDL) allocation under uncertainty. To convert the traditional direct simulation-optimization model into our indirect equivalent model framework, we proposed a two-step strategy: (1) application of inter...

Proposition O was created to help the City of Los Angeles comply with the Total Maximum Daily Load (TMDL) requirements under the Clean Water Act. In this study, the effectiveness of the Proposition O projects in Los Angeles River watershed was examined to show whether it achieves the goal of meeting water quality standards. Our analysis shows the most effective single project will remove at mos...

Today there are many well-established computer models that are being used at different spatial and temporal scales to describe water, sediment, and P transport from diffuse sources. In this review, we describe how diffuse P models are commonly being used in the United States and Europe, the challenge presented by different temporal and spatial scales, and the uncertainty in model predictions. I...

With mounting scientific evidence demonstrating adverse global climate change (GCC) impacts to water quality, quality policies, such as the Total Maximum Daily Loads (TMDLs) under U.S. Clean Water Act, have begun accounting for GCC effects in setting nutrient load-reduction policy targets. These targets generally require reductions attaining prescribed standards (WQS) by safe levels of concentr...