URBAN STORMWATER MANGEMENT-AN MS4 SUCCESS STORY FOR WESTERN MICHIGAN UNIVERSITY

Regulation of stormwater runoff is increasing throughout the United States.The Environmental Protection Agency(EPA)and state agencies are beginning to move toward effluent and/or load limits for pollutants in stormwater.Compliance costs for treating urban stormwater runoff,especially in highly-developed areas where retrofits are required,will only continue to increase.

THE COST OF MANAGING STORMWATER

INTRODUCTION Stormwater has long been recognized as a substantial contributor to water quality impairments.Development has increased the area of impervious surfaces and disrupted the natural flow path for precipitation.In developed areas,large volumes of untreated stormwater runoff increase erosion and pollutant transport to surface waters.Regulators have designed programs to address the water quality impacts of stormwater and regulated entities are in the process of figuring out how to comply with these measures.Financial burden often is cited as a major reason for slow implementation and lack of compliance with stormwater regulations(NRC,2009).Regulated entities have argued that the permit requirements are overly burdensome and unrealistic;however,it is still too early to determine the full financial burden of stormwater regulation.Although the regulations were enacted several years ago(and continue to evolve),many entities are still in the early phases of the implementation process and are trying to determine how to integrate stormwater controls into existing infrastructure.In addition,municipalities often have limited information about the cost of retrofits.The cost of compliance with stormwater regulation is one of the major unknowns facing municipalities and other regulated stormwater dischargers.Regulated entities should expect to incur high costs associated with stormwater controls,especially in areas that are already highly developed.Exactly how high these costs might be is uncertain.This makes it very difficult for decision makers to plan and budget for stormwater controls.As a result,many municipalities have delayed implementing these measures despite increasing pressure from regulators.Entities soon will have to begin financing and implementing stormwater controls.This paper illustrates the lack of,and uncertainty with,cost data available to planners and decision makers and provides an example where a regulated entity applied a localized analysis to cost effectively achieve stormwater reductions and compliance goals.

Evaluation of a GIS-based watershed modeling approach for sediment transport

In order to improve water quality and restore impaired watersheds,managers need to make decisions using data that are able to gather.Data collection can be expensive,tedious and time consuming.Not all watershed managers have sufficient budgets to undertake such exercises.In such situations using modeling approach makes sense.The Sediment Nutrient Assessment Program(SNAP)is a functionally distributed model.It uses Geographic Information System(GIS)-based methodology employing commonly used Revised Universal Soil Loss Equation(RUSLE)to estimate the amount of erosion that can occur in the study area and Flux model for estimating the sediment transport.By adopting this methodology a modeler can estimate fractions of sediment contributions from the three landforms(upland,surface tiled,riparian).An intermediate result is mapping of areas producing erosion at rates above,below and equal to tolerable rates for each soil type.The model works best on smaller watersheds(<4,000 hectare)where staff have time and resources to inventory water quality.A good understanding of the watershed is needed to validate the model outputs.The model implementation is relatively cheap,cost effective and easy.Existing data and freely available information in the public domain are used for computations.It takes a multifaceted and holistic approach by integrating current,localized research literature,field surveys,water quality data,and GIS into one tool for refining watershed management decisions.The SNAP model serves as a first stage of analyzing as to how bad the sedimentation problem is with limited resources.