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Mitigation technique.
· Reconsider roadway and drainage design to minimize effects on surface water features.
Strategies may include the following:
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.
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.
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.
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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 "may diminish"
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 citizen's 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 project's 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.
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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.
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