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121 CHAPTER 5. WATER QUALITY AND DRAINAGE OVERVIEW Connections between water quality issues and environmental justice may not be apparent at first glance, but there are several possible links. Natural physical laws and topography dictate the design of water quality and drainage improvements, and the location and function of these improvements could have distributive effects. Additionally, the associated improvements typically include a number of subjective design issues that can affect the quality of the visual environment. The very essence of water quality improvements suggests a net positive result for society. You should, however, consider a wider range of interests than has typically been done in the past to ensure that protected groups are not disproportionately impacted by the proposed improvements. A brief case study presented later in this chapter provides an example of why environmental justice should be addressed when evaluating how transportation system changes affect water quality and drainage. The state-of-practice discussion below begins with a broad look at current water quality and drainage engineering practices at the level appropriate for environmental document preparation. Common methodologies and engineering tools used to study water quality and drainage impacts are presented systematically, along with recommended approaches on how to extend these methods to allow for effective environmental justice assessment. Links to Web sites and other information are provided for those seeking more detailed information regarding the tools and processes used in the engineering analysis. The methods discussion draws connections between environmental justice issues and the engineering analyses associated with water quality and drainage design. Strategies and checklists are presented to help practitioners seamlessly incorporate environmental justice considerations into traditional analyses. The chapter closes with the Camp Coldwater Springs case study as an example of the connections between drainage design and environmental justice. STATE OF THE PRACTICE The current environmental impact analysis process as it pertains to water quality and drainage is made up of five general steps. 1. Evaluate existing conditions. 2. Evaluate regulatory agency jurisdiction and requirements. 3. Evaluate impacts to groundwater quality and quantity. 4. Evaluate water quality impacts to natural water bodies. 5. Evaluate water quantity impacts to natural water bodies. Each project will require its own unique level of emphasis for each of the general steps listed above. The following is a short summary of the components that make up the evaluations required for an environmental effects analysis.
122 Evaluating existing conditions This evaluation includes identifying the overall project limits for potential build and no-build options. The evaluation must be of sufficient detail to identify surface drainage patterns. An understanding of the topography of the project area and of points âdownstreamâ of the project limits must be developed for a successful evaluation. Typical resources used for this evaluation include the following: ⢠Aerial photos and contour maps (either commissioned specifically for a given project or provided by local government planning/engineering departments); ⢠Geographic information system (GIS)-based mapping (generally provided by local government planning/engineering departments); ⢠National Wetland Inventory; ⢠State public waters information; ⢠United States Geological Survey (USGS) quadrangles; and ⢠City and county drainage information. Field investigation and verification of the mapping information also should be conducted as part of this evaluation. The existing conditions evaluation should include the modeling of runoff in the project area based on current surface topography and soils/pavements, as well as on improvements such as ponds, pipes, and channels. A common modeling approach is presented in the âEvaluating water quality impacts to natural water bodiesâ discussion on page 124. Evaluating regulatory agency jurisdiction and requirements This component involves developing a list of all local, regional, state, and national agencies that may have an interest in the project based on the scope of the affected area. The delineation of this area should include the project limits and downstream areas. Agencies involved may be either stakeholders or regulating agencies. Agency jurisdictions and concerns will often overlap, and open communication among agencies is necessary to ensure that project requirements are complementary, not contradictory, to each other. Tables 5-1 and 5-2 list typical agencies that might be included and their respective areas of concern. This part of the evaluation typically requires several meetings with the stakeholder agencies to compile their specific concerns and requirements, as well as to determine which permits will be required as part of the project. A complete understanding of the cumulative agency requirements is necessary to develop the scope of the proposed improvements as they relate to water resource issues. Evaluating impacts to groundwater quality and quantity Typical groundwater impacts occur as a result of construction dewatering process improvements that involve permanent excavations below the existing groundwater table. Dewatering processes may result in infiltration of pollutants into the groundwater from runoff or ponding areas.
123 Table 5-1. Local and regional coordinating agencies for water quality and drainage Area of concern Municipalities Watershed organizations Lake associations Soil & water conservation districts Coastal shoreline organizations Water quality Water quantity System design and connections Best management practices Groundwater quality Shoreline erosion control Habitat Table 5-2. State and federal coordinating agencies for water quality and drainage Area of concern Natural resources agency Pollution control agency EPA1 FEMA2 Corps of Engineers U.S. FWS3 Water quality Water quantity NPDES4 regulations and guidelines Wetland Conservation Act Navigable waters Floodplains Wildlife habitat Fisheries Lakes and streams 1. United States Environmental Protection Agency 2. Federal Emergency Management Agency 3. United States Fish and Wildlife Service 4. National Pollutant Discharge Elimination System
124 Permanent excavations may ultimately alter groundwater elevations in the project area. Analysis should include estimated rates and volumes associated with groundwater infiltration from pond areas and groundwater exfiltration into sewers, ponds, and subdrainage systems. Generally, groundwater quality is not adversely affected by infiltration from storm water detention basins collecting runoff from roadway areas. Recharge from storm water pond infiltration is often beneficial to groundwater. Special cases such as runoff from industrial sites and/or the presence of chemicals, such as deicing fluids from airport operations, in the runoff stream may cause regulating agencies to require measures to limit infiltration. Existing pollutants in the soils located between water quality ponds and groundwater tables may also cause agencies to require limitation measures. Modeling tools commonly used for evaluating groundwater impacts include the following: ⢠FEFLOW (Finite Element Flow): This program provides an advanced 2-dimensional and 3-dimensional environment for performing complex groundwater flow, contaminant transport, and heat transport modeling. ⢠GMS 4.0 (Groundwater Modeling Software): GMS is a comprehensive program with tools for every phase of a groundwater simulation, including site characterization, model development, post-processing, calibration, and visualization. Evaluating water quality impacts to natural water bodies Typical water quality impacts to natural water bodies include the introduction of pollutant-laden sand and silt into runoff streams that originate from impervious or paved surfaces. Phosphorus is a commonly targeted pollutant; however, metals and salts are also found in runoff generated from roadway surfaces. Typical water quality treatment options include the construction of sedimentation ponds, infiltration areas, and hydraulic structures, such as grit chambers, to remove pollutant-laden sediments from the runoff stream. Many municipalities and watershed organizations require that water quality ponding improvements be constructed to conform to the National Urban Runoff Program (NURP) standards. However, requirements may vary depending on the area of the country and on existing conditions prior to improvement. The most common limiting factor for water quality improvements is the availability of land to construct water quality ponds. This can be especially problematic in developed corridors. Modeling tools to evaluate water quality impacts are commonly used in conjunction with topographic maps and land use and zoning information. The most commonly used model is the P8 Urban Catchment Model. P8 is a U.S. Environmental Protection Agency (EPA) computer model for predicting the generation and transport of stormwater runoff pollutants in urban watersheds. Continuous water-balance and mass-balance calculations are performed on a user- defined system consisting of watershed, particle classes, water quality components, and storage and treatment devices. Evaluating water quantity impacts to natural water bodies Water quantity impacts on natural water bodies often include stream erosion and higher flood levels on streams, wetlands, and lakes. These impacts are mostly due to increased rates of runoff
125 and, to a lesser extent, to increased volumes of runoff resulting from impervious or paved surfaces. Typical options complement existing water quality treatment options and primarily include the construction of ponds to slow down or detain runoff before it enters natural water bodies. Most regulating agencies require that the rate of runoff from a project not exceed the rate of runoff under existing conditions. This requirement may stand whether the existing condition is a natural or a built environment. Evaluation of water quantity impacts includes an analysis of floodplain areas to ensure that the project does not ultimately reduce the available flood storage. Reduction of floodplain storage volume in one area may require the excavation of new floodplain storage volume in another area. Tools commonly used to evaluate water quantity impacts include engineering hydrologic and hydraulic formulae and computer modeling software, such as the Hydraulic Engineering Center (HEC)- River Analysis System (RAS), the HEC-2, and the Storm Water Management Module (SWMM) in conjunction with topographic maps and storm drainage infrastructure as-built information. Recommended applications of these models are summarized below. ⢠Corps of Engineers Hydraulic Engineering Center â River Analysis System â HEC-RAS is a water surface profile model for steady and unsteady one-dimensional, gradually varied flow in both natural and constructed river channels. â HEC-2 â HEC-2 is a water surface profile model for steady, gradually varied flow in natural and constructed channels. ⢠EPA â Storm Water Management Module â SWMM is a storm water and wastewater management modeling package for analyzing urban drainage systems and sanitary sewers. The model combines hydrology and hydraulics with water quality. An application known as MIKE-SWMM provides users with a complete, graphical, easy- to-use interface. The data output provided by the models listed above are only as accurate as the quality of the input. For environmental document preparation, the level of necessary input detail is generally less than that needed for final design purposes. Input data generally is obtained from existing topographic maps, groundwater contour maps, and the preliminary plans of the proposed improvements, which illustrate changes in impervious areas, grading, and surface-water routing. SELECTING AN APPROPRIATE METHOD OF ANALYSIS The following is a discussion of methodologies for predicting the extent to which the water quality and drainage components of a transportation system change would differentially or severely affect protected populations. The design of water quality and drainage improvements generally is dictated by natural physical laws and topography, as well as by existing impediments in the built environment. Generally, improved water quality will equally affect all people using the resource, and mitigation improvements related to water quality and drainage will thus benefit society as a whole. Because regulations require either no net change or improvement in water quality and quantity characteristics, there will be little possibility for differential effects in most situations. However, the potential for distributive effects may result from situations such as the following:
126 ⢠A protected population is the predominant user of the impacted resource. ⢠A protected population uses the resource differently than the population as a whole. ⢠Impacted areas and mitigation areas are distributed unequally among populations. ⢠The proposed water quality or drainage improvements will affect the visual and aesthetic quality of the project site or sites. In the case where a protected population group is the predominant user of the impacted resource, the group would disproportionately experience any adverse or beneficial effects to the resource. Where the protected population uses the resource differently than the general population, it may be necessary to evaluate impacts based on type of use. A common example would be Native American use of fishery resources for subsistence compared to general population use of the same resources for recreation purposes only. When impacted areas and mitigation areas are distributed unequally among population groups, the problem is similar to many other distribution problems discussed in this guidebook. An example would be reducing flood plain storage in one area and undertaking an offsetting excavation project in another area. The project could differentially affect protected populations depending on their proximity to, and use of, the construction and excavation areas. The potential for water quality and drainage mitigation projects to cause distributive visual and aesthetic effects can be evaluated using methods explained in Chapter 11. The approach we recommend for evaluating impacts due to water quality and drainage improvements involves three steps. Step 1 â Identify the scope of the proposed water quality and drainage improvements and alternative improvements based on engineering judgment and the applicable regulations of governing jurisdictions as outlined above. Step 2 â Evaluate whether or not the improvements affect protected populations using the checklists outlined below. Step 3 â Modify or alter the scope of the proposed improvements as necessary and practical to minimize or eliminate impacts to protected populations. METHODS The methods for assessing likely water quality impacts of a proposed transportation project are summarized in Table 5-3. The methods presented in this chapter are somewhat different in nature than those in most other chapters of this guidebook in that they consist of checklists. The five checklists are intended to raise the salient environmental justice considerations related to water quality when significant changes to the transportation system are contemplated. The checklists are organized to ensure assessment of the following areas: ⢠Land acquisition, ⢠Visual quality, ⢠Accessibility,
127 ⢠Groundwater, and ⢠Surface water quality and quantity. These checklists can be used individually or in combination as necessary to evaluate water quality and drainage issues for the project in question. Table 5-3. Summary of methods for analyzing water quality and drainage effects Method Assessment level Appropriate uses Use when Data needs Expertise required 1. Land acquisition checklist Screening/ detailed Project/ corridor assessment Land acquisition could impact or displace protected populations Low Records review, survey/interview 2. Visual quality checklist Screening/ detailed Project/ corridor assessment Visual quality effects of water quality improvements could affect protected populations Low Visual quality design and communication 3. Access- ibility check-list Screening/ detailed Project/ corridor assessment Improvements impair access to water resources Low Survey/interview 4. Groundwater quality checklist Screening/ detailed Project/ corridor assessment Improvements have the potential to affect groundwater quality or quantity Medium GMS 5. Surface water quality checklist Screening/ detailed Project/ corridor assessment Improvements have the potential to affect surface water quality or quantity Medium HEC-RAS, HEC-2, SWMM Checklist 1. Land acquisition Water quality and drainage improvements often require that land be acquired to construct holding ponds, stilling basins, swales, and culverts. Although the locations of these improvements generally are determined by the topographical elevations of the land and the physics of water flow, there may be some flexibility in the siting of improvements. Check for: Does the affected area include protected populations? Suggested approach. Conduct a threshold analysis using the most recent census block and block-group information or more detailed information if it is available from local governments or metropolitan planning organizations (MPOs). Verify findings by conducting a field survey and interviewing persons with local knowledge of the area. Refer to Chapter 2 for more information. Will any of the proposed acquisitions separate members of protected population groups from their homes or other properties? Examples would include minority, low-income,
128 disabled, elderly, or single female head of household homeowners, tenants or property owners. If the answer is yes, compile a list of the properties and answer the following checklist question. If the answer is no, there are no adverse effects to protected populations. Suggested approach. Perform a records review to identify the property owners and any tenants. Determine if any are members of protected population groups by conducting personal interviews or surveys (see Chapter 2 for a suggested questionnaire). Are there other options or mitigation measures that could be implemented in lieu of displacing persons in protected population groups? If the answer is no for any of the listed properties, review the mitigation techniques and answer the following checklist questions. Mitigation techniques. ⢠Consider locating ponds either downstream or upstream of optimal locations if it would mean less impact to affected populations and if water quality/quantity issues would not be overly compromised. ⢠Consider alternatives to ponds, including grit chambers, underground detention, or mechanical treatment methods that reduce or eliminate the need for large pond areas and decrease the number and size of necessary land acquisitions. Be aware, however, that the cost of these methods generally is much higher than ponding for an equivalent result. Would the unmitigated acquisition of land owned by members of a protected population or the displacement of homeowners and tenants cause an economic or personal hardship for the affected individuals? If so, consider the following information. Discussion. Such a situation can be avoided in most cases. An exception might occur in highly populated built environments where topography and project design features severely restrict the available options. In such situations, every effort should be made to negotiate fair and reasonable condemnation terms to satisfy property owners. Assistance should be provided to displaced individuals. Because these situations are often very contentious, the responsible agency should take proactive steps to prepare a justification in the event that a formal complaint or lawsuit is filed. Do the unmitigated acquisitions disproportionately impact members of protected population groups? If so, it will be necessary to either alter the project design or justify the action. Discussion. Any evaluation that shows no disproportionate impact may be contested. To prepare for this eventuality, the evaluation should consider the proportion of affected property owners and displaced persons in protected population groups relative to the population proportion in the study area and in comparison areas. See the method for threshold analysis described in Chapter 2 and the related discussion, âLimitations of using comparison thresholds in environmental justice assessment.â
129 Checklist 2. Visual quality Many of the improvements associated with water quality and drainage systems are constructed within the public realm and are highly visible elements of the connection between public transportation infrastructure and the natural environment. Aesthetic design of water quality and drainage improvements can range from functional and utilitarian to highly attractive features that enhance the surrounding built or natural environment. Protected populations should be provided with meaningful public involvement that proactively solicits input and provides access to information concerning aesthetic design improvements. Chapter 11, Visual Quality, provides a much more in-depth analysis of this issue as well as techniques for evaluating visual quality impacts of water quality and drainage improvements. The following checklist can be used to evaluate visual quality effects of water quality and drainage elements. Check for: Is the affected area within the activity space where protected populations live, work, take part in recreational activities, or otherwise spend significant amounts of time? If the answer is yes, go to the following checklist question. If the answer is no, there would be no adverse effects to protected populations. Suggested approach. Use an appropriate combination of the techniques described in Chapter 2 to identify the presence of protected populations. Would the proposed water quality and drainage improvements be visible to members of protected populations? If yes, go to the following checklist question. If no, there would be no visual quality impacts. Suggested approach. As a first step, use GIS or a desktop program to overlay the location of improvements on a map of protected populations. If improvements are located within the activity space of protected populations, consider conducting a field survey or using GIS, as appropriate, to perform a line of sight, view-shed, or some other type of visibility analysis. Perform a visual quality assessment. Do results of the assessment indicate that visual quality would be adversely affected? If so, go to the following checklist question. Suggested approach. Perform an appropriate visual quality assessment. Techniques appropriate for identifying visual quality impacts to affected populations are provided in Chapter 11. What are the most appropriate mitigation measures to alleviate adverse effects? Mitigation techniques. ⢠General aesthetic: Consider incorporating a high level of aesthetic into the visible or exposed portion of water quality and drainage improvements, thus making them an amenity to the community instead of a detriment. Consideration should be given to making the improvements blend with the natural landscape.
130 ⢠Recreation opportunities: Consider incorporating trails for recreation and basic transportation around and through the improvement areas. ⢠Interpretation and education opportunities: Consider providing interpretation of the water quality improvements via signage (multilingual as appropriate) for educational purposes. Checklist 3. Accessibility Transportation improvements, including roadway widening or access control, and their associated storm water ponds, culverts, and channels may eliminate public access to natural water bodies and may adversely affect protected populations. Chapter 7, Transportation User Effects, goes into greater detail about how to evaluate accessibility. The following are some ideas specifically related to water quality and drainage. Check for: Is there existing recreational access and use of water bodies in the project area for activities such as fishing or swimming? Be sure to ascertain whether specific population groups use the water bodies differently than the general population. Suggested approach. Generate a list of the water bodies in the affected areas. Using expert knowledge, determine if any of the water bodies are used for recreational purposes. Review the list and findings with members of protected population groups through interviews, public meetings, focus groups, surveys, or some other form of feedback. Will the proposed water quality or drainage improvements reduce accessibility to water bodies used for recreation or reduce the level of safety in traveling to or using the water bodies? If so, consider appropriate mitigation techniques. Mitigation techniques. ⢠Consider as part of the project providing alternative access for fishing, swimming, or other recreational uses. An example would be a publicly accessible pier or dock in a safe location that does not compromise the safety improvements included with the roadway or the water quality and drainage improvements. ⢠Dual-purpose improvements could be considered, such as designing access bridges or trails for maintenance of outlet structures to also accommodate public use. Are there any safety issues associated with the proposed water quality or drainage improvements? Consider issues such as whether the area is near parks, day care centers, residences, or other areas where children play. If so, consider appropriate mitigation techniques. Mitigation techniques. ⢠Consider the use of fencing to protect people from potentially dangerous intake structures or other dangerous drops. Fencing may also be considered around ponds, although it may detract from the overall aesthetic of the area.
131 ⢠Consider grading the site to provide gentle slopes around ponds (3:1 to 5:1) to reduce chances of children falling into water. ⢠Plantings and landscaping treatments such as boulders and thorny shrubs improve aesthetics and tend to keep curious children and adults a safe distance away from ponding areas. ⢠Rescue items such as boards for thin ice rescue or life rings and rope may be placed near the pond and marked for emergency use only. ⢠Structures with pipes large enough to crawl or walk in should include fencing or gates with locks to prevent the public from entering, while allowing access for maintenance personnel. Checklist 4. Groundwater quality and quantity Transportation improvements often involve excavating and filling areas of the natural landscape. Drainage improvements typically require underground pipes several feet below the roadway and the construction of drainage basins at or near the existing water table. The environmental analysis should consider whether or not potential impacts to groundwaterâsuch as lowering the groundwater elevations in a localized areaâwill adversely impact protected populations. Check for: Are shallow private wells being used for domestic use? Some protected populations are more likely to lack the economic means to construct deep wells for domestic water use, and therefore are more likely to experience the adverse effects of changes to shallow groundwater elevations in their area. Is there an interface between groundwater and surface water in the project area, such as springs and water falls? In areas where groundwater and surface water meet, any impacts to groundwater elevations could have significant impacts on surface water features. Such impacts could adversely affect protected populations because they may be more likely to utilize the surface water for domestic use or may value the resource more highly than other population groups. Does the affected area encompass any historic settlements? Many historic settlements and indigenous peopleâs camps were built around natural springs; it is common for historic sites to be located at such locations. If any of these situations exist in the study area, determine if there are impacts to protected populations using techniques described in Chapter 2. In the case of such impacts, consider the following mitigation techniques: ⢠Reconsider roadway and drainage design to minimize effects to groundwater. Strategies may include the following: â Raising roadway grades and pond elevations. â Designing ponds that are larger and flatter rather than deeper with smaller areas.
132 â Designing ponds to infiltrate water back into the ground, and thus assure no net loss to the groundwater balance. â Taking measures to seal joints of deep sewer pipes to minimize infiltration of groundwater into the pipes and drainage system: ⢠Pumpable grouts can be the most cost effective and ⢠Trenchless lining of pipes with cured-in-place lining systems may also be considered. â Isolate the roadbed from the groundwater table with concrete, clay, or a geotextile lining system. ⢠Provide potable water supplies to homes by extending the local water distribution network if feasible. If no water distribution network exists, consider drilling deeper wells for the affected properties. ⢠Recreate water flow for springs and waterfalls using mechanical means such as pumping or municipal water systems. This option is only feasible for low-volume flows and short water falls. The construction of a mechanical system may not be possible without causing temporary damage to the natural water feature and thus may defeat its own purpose. Checklist 5. Surface water quality and quantity Transportation improvements nearly always affect the surface water quality and quantity of the surrounding area. Drainage improvements are included with transportation projects to convey storm water away from the roadway and toward the natural water body. Such improvements typically involve underground pipes, ditches and the construction of drainage basins to conduct, store and treat surface water. These improvements often result in modifications to the physical shape, size, or dynamic characteristics of existing streams or ponds (i.e., water movement that is faster, slower, higher, or lower). The environmental analysis should consider whether or not the potential impacts to surface water quality caused by raising high water elevations in a localized area would adversely impact protected populations. Examples include increasing groundwater flows and subsequent erosion problems. Check for: Does the area include existing surface water elements such as lakes, streams, rivers, or wetlands that will be affected by the improvements? Connections to such surface water features should automatically qualify for additional analysis. Also consider if existing surface water that currently runs to natural water bodies will be diverted elsewhere, thus reducing the natural recharge of those water bodies. Suggested approach. If any of these situations exist in the study area, identify any impacts to protected populations using techniques described in Chapter 2. If so, consider the following mitigation techniques.
133 Mitigation technique. ⢠Reconsider roadway and drainage design to minimize effects on surface water features. Strategies may include the following: â Ensuring that water quality is maintained or enhanced as it enters natural water bodies through use of ponds, grit chambers, or vegetated swales. Generally, regulatory agencies will set requirements that ensure this is accomplished. â Alter pond design to reduce or increase the high-water level as desired. If there are homes near ponding areas, it is best to design a pond with the lowest possible high- water elevation, thus reducing the potential for flooding or property damage to the residences. Designing ponds that are larger and flatter rather than deeper and smaller will result in lower flood elevations. â Utilize structures within the roadway to improve water quality and quantity issues if ponding areas create adverse impacts to protected populations. Examples include grit chambers, vortex separator structures, and underground pipe chambers. RESOURCES 1) An overview of the National Wetlands Inventory (NWI) and information on how to obtain wetlands maps and other information is available at the NWI Web site, http://www.nwi.fws.gov. The U.S. Fish and Wildlife Service also provides an online map for locating wetlands, available from http:// wetlands.fws.gov/mapper_tool.htm. 2) There are numerous online resources for downloading digital elevation models, topographic maps, and other GIS data useful for performing water quality and drainage evaluations. Many states have GIS data clearinghouses that offer a large amount of information either free of charge or for a minimal fee. The GIS Data Depot provides a large volume of GIS data for the entire U.S. Most of the data are free, although there is a charge for ordering information if they cannot be downloaded. The GIS Data Depot can be accessed at http://data.geocomm.com. 3) Additional Resources For more information about the National Pollution Discharge Information System, visit the EPA NPDES Web site at http://cfpub.epa.gov/npdes/stormwater/menuofbmps/ post.cfm. For more information about floodplain assessment and to obtain floodplain information visit the Federal Emergency Management Agency (FEMA) Web site at http://www.fema.gov/ fima. For information about wildlife and fisheries habitat, visit the U.S. Fish and Wildlife Service Web site at http://www.fws.gov. For more information on complying with the wetland conservation act and impacts to navigable waterways, visit the U.S. Army Corps of Engineers Web site at http://www.usace.army.mil.
134 Water Quality and Environmental Justice Case Study Camp Coldwater Springs, Minneapolis, Minnesota Introduction. This brief case study illustrates why it is important to assess environmental justice as it relates to water quality and drainage effects. Failure to identify issues in the planning stages can add significant costs during constructions and may delay, interrupt, or even stop projects completely. Background. In the late 1990s, the Minnesota Department of Transportation began a highway improvement project to reconstruct the interchange of Trunk Highway 55 and Trunk Highway 62 in Minneapolis, Minnesota. The reconstruction of Trunk Highway 55 had been in the planning and development stages since the 1960s, and an environmental impact statement (EIS) had been conducted for the improvement during the 1980s. The project area for the interchange is located on the border between two local watershed agencies, the Minnehaha Creek Watershed District (MCWD) and the Lower Minnesota River Watershed District (LMRWD). The interchange is near Camp Coldwater Springs, a historically significant spring utilized by Native American groups and early settlers in the region. As dewatering activities began at the construction site in December 2000, a noticeable decline in groundwater flow to the springs was noted by a MCWD scientist. The MCWD believed that the reduced flow was due to a storm water pond constructed as part of the interchange project. The issue became prominent as environmental and Native American groups began expressing their concerns. The situation culminated in a Minnesota law that prohibits any state action that âmay diminishâ groundwater flows to Camp Coldwater Springs. In addition, a District Court judge ordered the Minnesota DOT (MnDOT) to cease construction dewatering. A dye test confirmed a direct connection between the interchange and the springs, and it was determined that construction dewatering resulted in a substantial flow decrease in the springs. A design solution was developed, but it was not possible to prove that it would completely eliminate impacts to the springs. In September 2001 MnDOT terminated the project, citing the potential for future lawsuits from citizenâs groups. Analysis. In the particular case of the Highway 55 improvements, an EIS was completed in 1985, prior to Executive Order 12898 that requires environmental justice to be considered before undertaking major federal actions. The fact that environmental justice was not evaluated and that public values changed between the completion of the EIS and the construction period led to the perception that the projectâs environmental and cultural impacts were not adequately considered. The primary concern with the impact to Camp Coldwater Springs was not the environmental effect of reduced groundwater flow because the springs are not accessible to the public and are arguably not a critical recreational or ecological resource. Rather, the primary concern was the historical and cultural value of the springs, especially to Native Americans. Public issues with this project thus arose out of special values and beliefs held by specific population groups, some of them protected populations that placed cultural value on the natural condition of the springs. The checklists included with this guide would have triggered evaluation of the impact to Camp Coldwater Springs. Identifying potential impacts and mitigation measures may not have guaranteed that all of the affected interest groups would have been satisfied with the proposed project. However, it might have diffused some of the animosity that arose out of the perception that the issue was not addressed at all. Furthermore, if the EIS had identified the impacts, they may have been mitigated in the original plans. It is likely that mitigation costs would have been reduced and that the courts would have allowed the project to proceed.
135 For more information on the p8 urban catchment model see http://www.wwwalker. net/p8/. For more information on HEC-RAS see http://www.bossintl.com/html/hec- ras_overview.html. For more information on HEC-2 see http://www.bossintl.com/html/hec-2_overview.html. For more information on the SWMM and MIKE-SWMM see http://www.bossintl. com/html/mike_swmm_overview.html. For more information on the Camp Coldwater Springs case study see http://www. minnehahacreek.org/Projects_Permits/35-Crosstown/summary.htm. For more information on the FEFLOW model see http://bossintl.com/html/feflow_ overview.html. For more information on the GMS visit the GMS Resource Center at http://gms. watermodeling.org.
