highway 61 stormwater natural drainage and retrofit identification project (306-10-07)

Minnesota’s Lake Superior Coastal Program

Highway 61 Stormwater Natural Drainage and Retrofit Identification Project

August 2008

Prepared by the Minnesota Board of Soil and Water Resources

Julie A. McDonnell, Project Specialist, BWSR

Al Kean, Chief Engineer, BWSR

in consultation with Dwayne Stenlund, Erosion Control Specialist, MnDOT

Project No. 306-10-07

Contract No. A78906

This project was funded in part under the Coastal Zone Management Act, by NOAA’s Office of Ocean and Coastal

Resource Management, in cooperation with Minnesota’s Lake Superior Coastal Program.

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EXECUTIVE SUMMARY The Highway 61 corridor along the North Shore of Lake Superior is a unique and relatively sensitive area of Minnesota with regard to water quality in tributary streams and Lake Superior. This is also an area of concentrated population and increasing development. The North Shore area has three key natural characteristics that necessitate extra attention to protect water resources, including:

1) the land surface and streams slope steeply to Lake Superior; 2) the geology involves relatively thin topsoil over infertile subsoils with high clay and/or

gravel content, and exposed bedrock in many locations; and 3) cool stream temperatures are critical for trout and other indigenous species.

These conditions were reasons to investigate and identify retrofit opportunities within the Highway 61 corridor along the North Shore of Lake Superior. The USEPA’s National Management Measures to Control Nonpoint Source Pollution from Urban Areas (November 2005), Management Measure 10: Existing Development defines retrofits to involve the modification of existing surface water runoff control structures or surface water conveyance systems that were initially designed to control flooding, to also serve a water quality improvement function. Various local and regional resource management plans for the North Shore area were reviewed to identify priority areas for water quality protection and restoration, transportation infrastructure and other improvements planned, and related opportunities for retrofit practices. The Minnesota Department of Transportation (MnDOT) and other local and state government units have participated in several demonstration projects within the North Shore area in recent years to help identify effective practices to address the key natural characteristics of the area identified above. Best Management Practices (BMPs) for construction stormwater control in Minnesota and elsewhere also continue to develop. These and other information sources were used to identify retrofit practices applicable to the Highway 61 corridor along the North Shore. Recommended retrofit BMPs include:

1) Enhanced Runoff Velocity Control, Detention and Biotreatment a) Check Dams

1) Biologs / Biorolls 2) Rock Checks 3) Filter Berm Checks

b) Runoff Diversion Chevrons c) Rain Gardens and Bioswales (Bioretention)

2) Stormwater Inlet and Culvert Filters a) Storm Drain Inlet Filters b) Conduit Inlet or Outlet Filters

3) Accelerated Revegetation a) Erosion Control Blankets b) Compost Blankets c) Compost Logs d) Compost Grout

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Because topsoil is very limited, subsoils relatively infertile and bedrock exposed in much of the North Shore area, several of the recommended retrofit BMPs include the use of compost as a topsoil substitute and multi-purpose biolog fill material for accelerated revegetation of disturbed areas. Demonstration projects within the Highway 61 corridor and elsewhere have proven compost to be a very successful material for accelerated revegetation, as well as biotreatment of runoff. Maps, aerial photos and field investigations were used to identify drainage situations and locations that have opportunities for enhanced runoff energy dissipation, settling, infiltration and/or biotreatment prior to discharge into North Shore streams and Lake Superior. These locations include opportunities for implementation of one or more of the recommended retrofit BMPs. It is recommended that township, county and state transportation authorities, as well as cities, other government units and private individuals, pursue opportunities for implementation of retrofit BMPs to protect and restore the sensitive water quality of the unique North Shore and Lake Superior.

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Table of Contents Section Page

EXECUTIVE SUMMARY ………………………………………………………..…………. 2

INTRODUCTION…………………………………………………………………………….. 6

DEFINITION OF RETROFITS………………………………………………………………. 7

PROJECT PURPOSE AND SCOPE………………………………………………………….. 8

INFORMATION SOURCES AND SUMMARIES…………………………………………... 8

RECOMMENDED RETROFIT PRACTICES……………………………………………….. 10

Categories of Applicable Retrofit BMPs……………………………………………………… 11

Descriptions of Applicable Retrofit BMPs……………………………………………………. 11

1) Enhanced Runoff Velocity Control, Detention and Biotreatment………………………… 11

1)a) Check Dams……………………………………………………………………………... 12

1)b) Runoff Diversion Chevrons……………………………………………………………... 14

1)c) Rain Gardens and Bioswales (Bioretention)…………………………………………….. 15

2) Storm Drain Inlet and Culvert Filters……………………………………………………… 18

2)a) Storm Drain Inlet Filters / Inserts……………………………………………………….. 18

2)b) Conduit Inlet and/or Outlet Filters………………………………………………………. 19

3) Accelerated Revegetation………………………………………………………………….. 19

3)a) Erosion Control Blankets………………………………………………………………… 20

3)b) Compost Blankets………………………………………………………………………... 22

3)c) Compost Logs……………………………………………………………………………. 23

3)d) Compost Grout…………………………………………………………………………… 24

POTENTIAL RETROFIT LOCATIONS……………………………………………………… 25

OVERVIEW OF CONSTRUCTION STORMWATER PERMIT REQUIREMENTS……….. 25

CONCLUSIONS……………………………………………………………………………….. 26

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List of Figures

Figure Number and Title Page

1. North Shore Retrofit Identification Project Area ………………………………………… 6

2. Compost Biolog Check Dams in a Steep Drainageway…………………………………... 13

3. Compost Biolog Check Dams in Highway 61 Ditch……………………………………… 13

4. Riprap Check Dams……………………………………………………………………….. 14

5. Compost Bag Chevron Around a Culvert Inlet…………………………………………… 14

6. Compost Log, Compost and Blanket Chevron…………………………………………… 15

7. Example Rain Garden in an Urban Setting………………………………………………. 15

8. Bioswale in Highway 61 Road Ditch (2006)…………………………………………….. 16

9. Caribou River Wayside (Highway 61 Milepost 70.7)……………………………………. 17

10. Catch-All Stormwater Inlet Filter………………………………………………………… 18

11. Stormwater Outlet Filter………………………………………………………………….. 19

12. Cleaned Road Ditch, E. Shilhon Road, Lake County, near Highway 61………………… 20

13. Compost Blanket, Highway 61, Cook Co. (2003)………………………………………... 22

14. Compost Blanket, Highway 61, Cook Co. (2003)………………………………………... 23

15. Compost Logs and Blanket at Silver Cliff (2006)………………………………………… 23

16. Compost Grout of Rock Side Slope (2003)………………………………………………. 24

17. Compost Grout, Potential Application (2006)……………………………………………. 24

List of Appendices

Appendix A – Summary of Pertinent Water Quality and Related Information for North Shore Rivers and Creeks

Appendix B – Compilation of Local Government Plans Relevant to the Highway 61 Corridor – North Shore Retrofit Identification Project

Appendix C – Potential Retrofit Sites in the Highway 61 Corridor – North Shore Retrofit Identification Project

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If all of the world's water were to fit into a gallon jug, the amount of fresh water would be just one tablespoon full. Yet almost half of our nation's 3.6 million miles of rivers and streams are threatened or impaired. Search out practical tips on things you can do to protect and improve the quality of the rivers close to you.

– The Nature Conservancy Lake Superior contains approximately 10% of this relative tablespoon of fresh water worldwide and over 50% of the water in the Great Lakes. INTRODUCTION Lake Superior is an outstanding natural resource, as are its tributary streams and coastal zone. The watersheds of the tributary streams along the North Shore of Lake Superior include vast areas of forest and wetlands that help many of these streams run cool and perennial. Together with the nearshore zone of Lake Superior, these tributary streams provide critical habitat for fish and wildlife, as well as great attraction for recreation and associated development. Lake Superior is also a drinking water source for a number of communities along the North Shore. The Highway 61 corridor parallels the North Shore of Lake Superior from Duluth to the international border with Canada (see Figure 1).

Figure 1. North Shore Retrofit Identification Project Area

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Within the Highway 61 corridor along the North Shore of Lake Superior, there are three key natural characteristics that necessitate extra attention to protect water resources:

1) the land surface and streams slope steeply to Lake Superior; 2) the geology involves relatively thin topsoil over infertile subsoils with high clay

and/or gravel content, and exposed bedrock in many locations; and 3) cool stream temperatures are critical for trout and other indigenous species.

The Highway 61 corridor is where a majority of people live within the Lake Superior basin in Minnesota. This is a primary corridor for travel and recreation, as well as commercial and residential development (four cities, 12 towns, one Reservation, numerous businesses, resorts, campgrounds, and state parks). In each of the three counties through which the Highway 61 corridor passes (St. Louis, Lake, and Cook), the percent private land within 1 km of Lake Superior greatly exceeds the percent private land within the watershed (Schomberg, et al., 2006). Housing units and population have increased along the North Shore steadily since 1990, and are projected to continue to increase (Schomberg, et al., 2006). This rapid growth has driven the demand for second homes, resorts, services and improvements of the transportation system, increasing the amount of impervious surface by approximately 2,000 acres from 1990 - 2000 and necessitating substantial disturbance of vegetation, soil and bedrock. These trends typically have resulted in altered watershed hydrology with increased runoff, higher amounts of sediment and other pollutants and increased temperatures in some North Shore streams. Minimizing soil disturbance, accelerating restabilization of disturbed areas, and managing runoff rates and volumes associated with existing and new development are critical ways to restore and protect water quality along the North Shore. These objectives can be substantially achieved by implementing associated Best Management Practices (BMPs). Maintenance and improvement of existing transportation infrastructure, including roads, streets, parking areas and associated stormwater conveyance systems, are substantial reasons for soil disturbing work in the Highway 61 corridor associated with existing and new development. Stormwater runoff from transportation infrastructure can also be a significant source of suspended solids, nutrients, chlorides, metals and oil, as well as increased stormwater runoff temperatures. Existing runoff management systems along, and tributary to, the Highway 61 corridor provide substantial opportunities for retrofit BMPs. The Coastal Management Measures required by the Lake Superior Coastal Nonpoint Program include retrofit practices in areas of existing development as an important program component to protect and restore water quality. DEFINITION OF RETROFITS The USEPA’s National Management Measures to Control Nonpoint Source Pollution from Urban Areas (November 2005), Management Measure 10: Existing Development defines retrofits to involve the modification of existing surface water runoff control structures or surface water conveyance systems that were initially designed to control flooding, to also serve a water quality improvement function. This may involve modifying a structure or drainage system to increase runoff detention time, increase infiltration, trap sediment and associated pollutants, and/or filter out other pollutants (includes bioretention, biofiltration, biotreatment and bioreaction practices). Retrofits can also apply to redevelopment and improvement of existing development, particularly where land availability for water quality treatment practices is limited.

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PROJECT PURPOSE AND SCOPE The water quality of North Shore streams has been declining since the 1970s, based on monitoring since that time (MPCA 2002). Many of the North Shore streams that have been tested for water quality and temperature are found to be impaired and consequently have been listed on the State’s 303(d) impaired waters list. Waters of the State with an impaired status are required to be restored to the water quality standards applicable for their designated use. There appears to be a trend toward declining water quality in the Lake Superior watershed where urbanization and other development is increasing, particularly along the Highway 61 corridor. This is currently evident in streams between Duluth and Two Harbors, as well as the lower Poplar River in Cook County (MPCA 2002). Thus, there is a need to implement retrofits into maintenance and improvement of existing development that will help reduce pollutants entering North Shore waters. The Minnesota Coastal Nonpoint Program encourages retrofits within the Coastal Management Measures categories of Urban/Rural Runoff, Site Development, Existing Development, Pollution Prevention, Road and Highway Planning, and Wetland and Riparian Areas to “protect areas that provide important water quality benefits and/or are particularly susceptible to erosion and sediment loss”, and to “limit increases of impervious areas except where necessary”. The scope of this project involves the Highway 61 corridor from Duluth to the U.S.-Canada border. The project has a focus on retrofits associated with maintenance and improvement of existing transportation infrastructure and associated runoff management systems, as well as runoff management systems within existing development along the Highway 61 corridor. Many of the BMPs recommended for retrofits are also applicable for new development. This project report provides concepts and guidance for state agencies, local government units, developers, landowners and contractors regarding how to better manage the water resources in this region for water quality and habitat protection, while conducting road, street and parking area maintenance and improvement, as well as residential and commercial development within the Highway 61 corridor. BMP recommendations are focused on addressing the challenges presented by the key natural characteristics of the area identified above. INFORMATION SOURCES AND SUMMARIES Following are information sources that were researched for this project.

1) Water quality assessment data: Lake Superior Basin Plan, February 2004 Minnesota 303(d) impaired waters list (2006) An Assessment of Representative Lake Superior Basin Tributaries (MPCA 2002)

2) Basin, watershed and local water management plans: Lake Superior Basin Plan, February 2004 Local Water Management Plans for St. Louis, Lake and Cook Counties St. Louis, Lake, and Cook Soil and Water Conservation District Annual Work Plans

(2006)

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Land Use and Stormwater Management Plans for North Shore communities (as available)

Road Crossing Survey of Minnesota’s North Shore Tributaries to Lake Superior for Fish Passage (DNR 2004)

3) MNDOT maintenance and improvement plans/schedule for Highway 61 (2007-2024) 4) County Highway Department plans for road and ditch maintenance adjacent to Highway

61 (2006 - 2007) 5) Building Superior Coastal Communities, MN Sea Grant Publication (2006) 6) Best Practices for Meeting DNR General Public Waters Work Permit, GP 2004-001,

March 2006 7) Pertinent demonstration project experience in the region:

Great Lakes Commission Project – Applying Natural Restoration Techniques to Slope Restoration – Grand Marais Lake Superior Shoreline Area, MN

Great Lakes Commission Project – Grass Swale with Rock Checks and Biofiltration at Glensheen Mansion

8) MNDOT, Local Road Research Board and Federal Highway Administration publications: Improving the Design of Roadside Ditches to Decrease Transportation-Related

Surface Water Pollution, June 2003, 2004-11 (http://www.mrr.dot.state.mn.us/research/pdf/200411.pdf)

Erosion Control Handbook for Local Roads, 2003-08 (http://www.lrrb.gen.mn.us/pdf/200308.pdf)

MNDOT Erosion and Sediment Control Certification & E-Team Training Program 2001 (http://www.dot.state.mn.us/environment/pdf_files/TrnManCl.pdf)

9) Recent stormwater bioretention guidelines: Design Guidelines for Stormwater Bioretention Facilities, February 2006, Water

Resources Institute, University of Wisconsin System, Publication No. WIS-WRI-06-01 (http://www.aqua.wisc.edu/Publications/PDFs/StormwaterBioretention.pdf)

Minnesota Stormwater Manual, Chapter 12-6, Bioretention, Version 2, January 2008 (http://www.pca.state.mn.us/publications/wq-strm9-01.pdf)

Bioretention Basin, Code 712, Conservation Practice Standard, NRCS Minnesota, June 2008 (http://efotg.nrcs.usda.gov/references/public/MN/712mn.pdf)

10) Knowledge and experience of key individuals related to potential retrofit BMPs: Dwayne Stenlund, CPESC, Erosion Control Engineering Unit, MNDOT Todd Campbell, District 1 Hydraulics Engineer, MNDOT Staff of North Shore Soil and Water Conservation Districts

11) Site investigations along the Highway 61 corridor. 12) Various available literature regarding the effects of potential retrofit BMPs.

These information sources were used to help identify and prioritize locations along the Highway 61 corridor with water quality concerns (or increased likelihood of future concerns) that could

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benefit from retrofits, as well as to identify recommended retrofit BMPs and specific locations for potential retrofit BMPs. Appendix A is a Summary of Pertinent Water Quality and Related Information for North Shore Rivers and Creeks. This table consolidates pertinent information from a number of the above sources and helps catalog recently identified impairments, trends, concerns and related activities. This compilation includes available information about county and state highway construction project schedules. Appendix A illustrates that over time, North Shore stream water quality has been decreasing, impacts from nonpoint source pollution are increasing, and that a number of active projects and citizen/watershed groups are in place that are working on these issues. Water quality data for North Shore streams generally indicates a need to incorporate BMPs wherever feasible and practical, including retrofit BMPs within existing development. Review of this summary information identifies general priority locations where retrofit project implementation should be pursued (e.g. near stream reaches with impaired status or declining water quality and/or where upcoming state or county highway reconstruction will be conducted in the area, which could be an opportune time to install retrofits). Appendix B is a Compilation of Local Government Plans Relevant to the Highway 61 Corridor – North Shore Retrofit Identification Project. Many of these local and regional plans identify related priority concerns, trends and action items regarding water quality restoration and protection along the North Shore of Lake Superior. The Lake Superior Basin Plan provides an assessment of all of the watersheds within the basin, many of which cross the Highway 61 corridor along the North Shore. Although the local government plans tend to be relatively general with regard to North Shore stream priority concerns and action items, these plans identify specific water quality restoration needs for impaired waters along the North Shore, including the Sucker, Knife, and Poplar Rivers. Municipal stormwater management plans identify general and specific priority concerns and action items related to creeks, rivers and stormwater management infrastructure within the associated jurisdiction. RECOMMENDED RETROFIT PRACTICES As maintenance, redevelopment and new development occurs within the Highway 61 corridor along the North Shore (including both rural and urban areas), BMPs are and should be used to control surface water runoff and reduce associated pollutant loads to protect and restore water quality in creeks and rivers, as well as Lake Superior. This includes retrofit BMPs within existing stormwater conveyance systems, as well as innovative erosion control techniques during maintenance and improvement of transportation and stormwater infrastructure and other existing development. Retrofit BMPs can be implemented to slow, detain and retain water to reduce erosion, as well as to enhance settling, biotreatment, infiltration and evapotranspiration. Within the Highway 61 corridor along the North Shore, retrofit BMPs, as well as new development BMPs, should consider the 3 key natural characteristics of the area identified above that necessitate extra attention to protect water resources.

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Categories of Applicable Retrofit BMPs Recommended retrofit BMPs identified for the Highway 61 corridor can be organized into three general categories:

1) Enhanced Runoff Velocity Control, Detention and Biotreatment This category includes a number of practices that can be implemented as retrofits during maintenance or improvement of transportation infrastructure and other existing development for water quality restoration and protection, including:

a) Check Dams 1) Biologs / Biorolls 2) Rock Checks 3) Filter Berm Checks

b) Runoff Diversion Chevrons c) Rain Gardens and Bioswales (Bioretention)

Some of these practices utilize familiar methods and materials, while others utilize more innovative materials and techniques to protect and restore water quality.

2) Stormwater Inlet and Culvert Filters This category of retrofit BMPs includes:

a) Storm Drain Inlet Filters b) Conduit Inlet or Outlet Filters

These practices can provide filtration at the inlet or outlet of stormwater conveyance structures to collect debris and pollutants from road and parking lot runoff, as well as natural conveyance systems, before it enters Lake Superior or tributary streams. Filter media can include chemical treatment capability.

3) Accelerated Revegetation This category specifically addresses the challenging characteristic of thin, infertile topsoil and subsoil and exposed bedrock along the North Shore. Specific recommended practices include:

a) Erosion Control Blankets b) Compost Blanket c) Compost Logs d) Compost Grout

These practices can be implemented as retrofit BMPs during redevelopment and improvement of transportation infrastructure and other existing development, as well as for new development. There is some overlap between categories, such as the biotreatment that occurs with various applications of compost for accelerated revegetation. Descriptions of Applicable Retrofit BMPs 1) Enhanced Runoff Velocity Control, Detention and Biotreatment Highway 61 crosses numerous rivers and creeks along the North Shore that are tributary to Lake Superior. Road ditches along Highway 61 typically discharge directly into these rivers and creeks. Ditches along county and township roads that connect to Highway 61 convey runoff to

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these drainage systems. Streets and storm sewers within the cities and towns along the North Shore also convey runoff to these constructed ditches and natural drainageways, or directly to Lake Superior. Retrofit opportunities exist to enhance runoff velocity control, temporary detention and biotreatment within these drainage systems to protect and restore water quality. Materials, design and construction techniques for these types of practices have evolved substantially in recent years, improving the application and effectiveness of these practices in various settings, including the North Shore. The effectiveness of runoff velocity control, temporary detention and biotreatment practices is substantially related to the fact that the majority of precipitation events in the Midwest are relatively small. Therefore, based on frequency of occurrence, BMPs that better manage frequent, smaller precipitation and runoff events (including the “first flush”) can have major benefits for water quality. Temporary detention includes practices to reduce flow velocities and associated erosion, as well as to increase settling of sediment and adsorbed nutrients. Biotreatment BMPs can include:

bioretention practices, such as rain gardens and bioswales; bioreaction or biofiltration practices, such as bioroll check dams, filter berm check dams,

compost blankets, and compost grouting of riprap or gabion baskets. These practices utilize physical, biological and chemical processes including filtration, adsorption, nutrient uptake and use by plant materials, nutrient volatilization, ion exchange, microbial activity and other associated biological processes of soil and plants. Biotreatment BMPs often strategically integrate plants, plant materials, and soil (soft materials) with hard materials, such as rock, wire, geosynthetics and dimension lumber. The number and types of biotreatment practices continues to grow. The Minnesota Department of Transportation, other state agencies and local government units have demonstrated a number of these types of practices in the Highway 61 corridor along the North Shore and continue to develop these and other types of BMPs for erosion control and water quality protection and improvement. 1)a) Check Dams Check dams are often used as temporary and/or permanent erosion and sediment control practices in concentrated flow areas such as ditches, particularly where ditch grades are relatively steep. Check dams reduce flow velocities by concentrating energy dissipation at controlled through-flow and overflow locations. Many of the road ditches along the Highway 61 corridor have areas with relatively steep grades, such as near stream crossings and where roads are parallel to the general land slope toward Lake Superior. Many of these locations present opportunities to use check dams to reduce flow velocities and erosion potential, enhance vegetation development, increase sediment and nutrient trapping, and increase infiltration. Check dams create very small, temporary ponding areas. They generally do not have as a purpose to create permanent ponds. Check dams are often 6 inches to 2 feet in height and spaced at intervals in the ditch such that the toe elevation of a check dam is approximately the same as the crest elevation of the next downstream check dam. The height of check dams should reflect the materials used to construct

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the dams and applicable safety considerations at the site. It is very important that the ends of a check dam are constructed higher than the middle, to prevent concentrated flow at the ends and potential flanking of the structure (i.e. erosion around the ends). Check dams can be constructed with or without a foundation erosion control strip, such as geotextile, under and downstream from the check dam to provide a filter beneath the structure and a protected stilling area (i.e. for stilling of turbulent overflow) on the downstream side of the check dam. Biolog check dams (see Figures 2 and 3) can be placed and anchored individually across a ditch, or stacked and appropriately anchored to provide greater height. Compost-filled biologs provide a very good medium for growth of vegetation at the biolog to aid in erosion control, biotreatment and practice longevity. In both of the applications shown, the biologs were filled with compost. In Figure 2, the biologs were a retrofit along with compost beneath the original design of a turf reinforcement mat (TRM) within the channel, to provide an improved seedbed . In Figure 3, a compost blanket was also applied to the surface of

the road ditch to accelerate revegetation.

Figure 2. Compost Biolog Check Dams in a Steep Drainageway

Figure 3. Compost Biolog Check Dams in Highway 61 Ditch

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Riprap check dams (see Figure 4) can provide effective energy dissipation and flow aeration via localized turbulent flow through and over the structure. Organic material such as biologs, compost or wood slash can be placed within the structure or on the upstream face of riprap check dams to also provide biofiltration and biotreatment. Report number 2004-11, Improving the Design of Roadside Ditches to Decrease Transportation-Related Surface Water Pollution, June 2003, by MnDOT and the Local Road Research Board, demonstrated the use of a riprap check dam with a peat-filled gabion basket core zone for biotreatment. 1)b) Runoff Diversion Chevrons Bridges and culverts are typically located at low points along a road profile, the side slopes of road embankments adjacent to bridge abutment wing walls and the ends of conduits through the embankment are often steepened and these locations experience concentrated runoff from the road surface. Runoff diversion chevrons can be constructed of biorolls, biologs, or sand- or gravel-filled bags placed in the shape of a chevron (i.e. an inverted “V”) on the side slope of the road embankment over and

Figure 4. Riprap Check Dams

Figure 5. Compost Bag Chevron Around a Culvert Inlet

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around the end of a conduit (or half of a chevron near a bridge abutment wing wall) to reduce the effective slope and increase the length and roughness of the flow path of runoff from the road surface and embankment side slope to the bottom of the road ditch (see Figure 5 and Figure 6). Multiple rows of chevrons can be used where concentrations of runoff are high and road embankment side slopes particularly steep. Chevrons can also direct runoff from the roadway to a bioswale or another type of treatment area in the road ditch prior to the runoff flowing through a culvert or bridge under the roadway. 1)c) Rain Gardens and Bioswales (Bioretention) Bioretention enables stormwater runoff to be reduced in volume and improved in water quality through physical, chemical and biological processes. Rain gardens are relatively shallow bioretention areas, and bioswales are channels with flow through detention, both typically designed to capture and treat the first flush of runoff, with overflow for large events. Key characteristics of bioretention practices are listed below. Where soil permeability is conducive, these practices can substantially increase infiltration. Through increased infiltration and groundwater recharge, these practices can increase

Figure 7. Example Rain Garden in an Urban Setting

Figure 6. Compost Log, Compost and Blanket Chevron

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base flows to nearby streams to help maintain naturally lower stream temperatures. These practices typically are also aesthetic attributes to their surroundings. Figure 7 shows a rain garden that collects and treats runoff from road and parking surfaces. Figure 8 shows a road ditch along Highway 61 that has been transformed into a bioswale. Key characteristics of bioretention practices include:

creating increased rainfall absorption capacity and infiltration through increased surface and subsurface organic matter (plants, mulch and deep, healthy roots) and increased soil permeability (sometimes via engineered soil beneath a rain garden or bioswale involving the addition of compost and/or sand);

increased runoff detention through temporary storage above and below ground (ponded water and saturated soils are typically maintained no longer than 48 hours above and within the plant root zone) and at shallow depths (generally no deeper than 18 inches above the ground surface, with 6 to 12 inches more typical);

increased evapotransporation through strategic plant materials and increased water holding capacity in the soil profile. These practices are generally compatible with road ditches, boulevards and shallow drainageways where the contributing drainage area is relatively small. The Minnesota Stormwater Manual, Chapter 12-6, Bioretention (http://www.pca.state.mn.us/publications/wq-strm9-01.pdf) provides guidance for selecting and designing bioretention facilities. The University of Wisconsin has developed Design Guidelines for Stormwater Bioretention Facilities with the software RECARGA (http://www.aqua.wisc.edu/Publications/PDFs/StormwaterBioretention.pdf). The USDA-Natural Resources Conservation Service (NRCS), in consultation with state and local government units in Minnesota, as well as the University of Wisconsin and University of Minnesota, recently developed conservation practice standard 712, Bioretention Basin (http://efotg.nrcs.usda.gov/references/public/MN/712mn.pdf).

Treating the first flush of runoff is a key concept and method for water quality protection and restoration, particularly from urban areas and roadways, due to higher concentrations of nutrients and other pollutants during the first flush of impervious surfaces. In locations along the North Shore where subsoils are thick and have a high clay content, an underdrain may be necessary beneath bioretention Figure 8. Bioswale in Highway 61 Road Ditch (2006)

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basins to lower the water level in the bioretention basin within the typical maximum 48-hour time period required for vigorous plant health. Design guidelines for bioretention facilities in relatively impervious soils may also include replacing or engineering some of the underlying soil to increase its water holding capacity (for example through the addition of sand and/or compost, as noted above). These are important retrofit practices for cities, other developed areas and transportation corridors along the North Shore. Selection, establishment and maintenance of native plant materials are important elements of successful implementation of rain gardens and bioswales. Expertise in this regard continues to grow, as the use of bioretention and biotreatment BMPs continues to expand. This includes expertise regarding local native seed mixes, as well as live plant material selection, establishment and maintenance for these types of practices in different areas of Minnesota. The Minnesota Department of Transportation, Minnesota Board of Water and Soil Resources and a number of Soil and Water Conservation Districts in Minnesota continue to develop and hone this type of expertise. It is expected that applicable guidance documents will also continue to be developed and improved. There are numerous waysides, rest areas, scenic overlooks and other parking lots along the Highway 61 corridor, where rain gardens and/or bioswales could help improve the quality of surface water runoff. Many of these sites are located close to creeks and rivers and/or close to Lake Superior. Appendix C includes a list of identified locations organized by Highway 61 milepost number. As an example, Figure 9 shows a Caribou River wayside, where runoff from the parking area concentrates in a corner of the parking lot, overflows the curb and runs overland into the Caribou River. Installation of a rain garden and/or bioswale at this location could reduce erosion, help infiltrate runoff for temperature control and provide biotreatment of runoff from the parking area. In Grand Marais, homeowners reportedly have concerns about increased flows of water running down city streets during rain events. Rain gardens could be created adjacent to streets, including curb cuts, to collect, treat and reduce first flushes of runoff from city streets. Investigation of the underlying soils would need to be conducted to determine permeability and the potential need for underdrains. The Burnsville, MN Stormwater Retrofit Study and demonstration project (2006)

Figure 9. Caribou River Wayside (Highway 61 Milepost 70.7)

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(http://www.burnsville.org/DocumentView.asp?DID=449) demonstrated the implementation of rain gardens in an urban residential area that greatly reduced runoff volume and improved runoff quality. Many other rain garden implementation projects have been completed in Minnesota in recent years. The steep streets in Grand Marais and other North Shore towns make rain gardens more challenging, but not impractical. The multiple benefits of runoff volume and peak flow reduction, water quality improvement and aesthetics make rain gardens a great retrofit practice. 2) Storm Drain Inlet and Culvert Filters The Municipal Separate Storm Sewer System (MS4) program requires all but the smallest municipal and industrial stormwater systems to treat storm water discharge to the “maximum extent practicable.” It is generally understood that significant removal of suspended solids, hydrocarbons, sediment, metals and nutrients is a goal. Even in areas where MS4 requirements are not applicable, stormwater treatment is important. Urban areas with higher pollutant concentrations, such as roadways, parking lots and tourist centers can benefit from the use of catch basin inserts (filters) to trap pollutants prior to discharge to surface waters. 2)a) Storm Drain Inlet Filters / Inserts There are numerous manufacturers of storm drain inserts designed to filter trash, oil and other contaminants from stormwater runoff as it flows into storm sewer inlets. The following discussion presents examples that are not intended as endorsements for specific products. Geotextile Marathon Filters, Dandy Bag and Pig-Drain Inserts – These representative products involve filter bags connected to rigid frames that are inserted into storm drain inlets, as shown in Figure 10. Bags can include activated carbon in geotextile filter fabric. These products can filter litter, suspended solids, hydrocarbons, phosphorus, nitrogen, and heavy metals from stormwater. These filters can yield quantifiable results (i.e., pounds of sediment and trash prevented from entering surface water) in a relatively short period of time. They require periodic maintenance, but can be cleaned out at the rate of approximately three per hour. Looking at storm sewer inlets as point conveyances having direct impact to the receiving waters reinforces the opportunity and need to address these identifiable conveyances of contaminants

Figure 10. Catch-All Stormwater Inlet Filter

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to Lake Superior. Figure 10 shows an example of this type of retrofit BMP. Note that the insert includes an overflow area above the filter bag when the runoff rate is greater than can pass through the filter bag. MnDOT has retrofitted storm drains in St. Cloud, MN with Geotextile Marathon filters and the Imbiber Beads Imbicator and has found that these filters will capture 100% of trash and cigarette butts, as well as most sediment and numerous other pollutants. The Imbicator filters organic chemicals including gasoline, fuel oil, chlorinated solvents, and other aromatic solvents from stormwater and changes color to indicate when the filter needs to be replaced. The filter can remove a total of 2½ gallons of oil before needing replacement. This type of retrofit BMP could be installed in urban areas that discharge stormwater directly to Lake Superior or its tributary creeks and rivers, particularly high use areas. Potential retrofit locations include Canal Park in Duluth, downtown Duluth, the cities of Two Harbors, Silver Bay, Grand Marais and other developments that collect stormwater runoff into storm sewers and discharge it directly to sensitive waters. Because there is a limited number of these urban storm drain systems along the Highway 61 corridor, application of this retrofit BMP could be feasible and manageable in key locations from an ongoing maintenance perspective. 2)b) Conduit Inlet and/or Outlet Filters Contaminants from urban and rural stormwater runoff can include various types of trash and materials that have a biological oxygen demand when they decompose. Culvert inlet and outlet filters can be installed at road crossings of creeks and smaller drainageways to collect these types of pollutants. Figure 11 shows one such filter for the outlet of a stormwater conduit. Periodic clean out is an important requirement for this type of practice. 3) Accelerated Revegetation Recall the 3 key natural characteristics of the North Shore identified earlier in this report:

1) the land surface and streams slope steeply to Lake Superior; 2) the geology involves relatively thin topsoil over infertile subsoils with high clay and/or

gravel content, and exposed bedrock in many locations; and 3) cool stream temperatures are critical for trout and other indigenous species.

Figure 11. Stormwater Outlet Filter

20

These characteristics make revegetation after disturbance of existing vegetation or natural armoring of drainageways quite challenging, but also very important for water quality protection and restoration in the Highway 61 corridor along the North Shore of Lake Superior. Accelerated revegetation can be a retrofit BMP, as well as a new construction BMP. Maintenance and improvement of transportation infrastructure is a very important yet challenging activity along the North Shore, because it involves extensive surface drainage systems that necessarily encounter the above 3 key natural characteristics of the area. Simple clean-out of road ditches (including city, township, county and state roads) can be a significant source of erosion, suspended solids and sedimentation in North Shore runoff conveyance systems that empty into high value creeks and rivers that flow to Lake Superior. Ditch cleaning typically involves scraping and regrading ditches to transport water away from roads and protect the road embankment from overtopping, erosion and/or a saturated subgrade. Road ditches in the Highway 61 corridor are typically excavated into infertile subsoils or bedrock, which is re-exposed during clean-out. Figure 12 shows an example road ditch clean-out excavated into a clay, glacial till subsoil. Although these can be challenging situations for reestablishment of vegetation, there are many products, such as erosion control blankets, in use today that can facilitate reestablishment of vegetation in these situations. In addition, relatively new practices have been demonstrated in the Highway 61 corridor along the North Shore, including compost blankets, compost logs and compost grout, to facilitate accelerated revegetation.

3)a) Erosion Control Blankets Erosion control blankets are used quite extensively statewide for erosion control and revegetation on steep, disturbed slopes. Within the Highway 61 corridor, there are many applications for various types to erosion control blankets. MnDOT Standard Specifications for Construction, 2005 Edition (http://www.dot.state.mn.us/tecsup/spec/2005/toc.pdf) includes a wide variety of erosion control blankets for various applications within Specification 3885. Following are key summary information from Specification 3885.

Figure 12. Cleaned Road Ditch, E. Shilhon Road, Lake County, near Highway 61

21

MnDOT Specification 3885 – Erosion Control Blankets

Category Material Types Service Life Use 00 Wood Cellulose 1S, NT, RD 6-8 weeks Flat areas, mowed areas 0 Wood Fiber 0S, RD 6-8 weeks Flat areas, mowed areas 1 Straw RD 1S, or Wood Fiber

RD 1S 6-8 weeks Flat areas, shoulder drain outlets,

roadway shoulders, and lawns. 2 Straw 1S, or Wood Fiber

1S

One Season Slopes 1v:3h to 1v:2h less than 15 m (50 feet) long, ditches with gradients of 2 percent or less, flow velocities less than 1.0 m/second (3.5 feet/sec.).

3 Straw 2S, or Wood Fiber 2S One Season Slopes 1v:3h to 1v:2h more than 15 m (50 feet) long, ditches with gradients of 3 percent or less, flow velocities less than 1.4 m/second (4.5 feet/sec.), flow depth 50 mm (2 inches) or less.

4 Straw/Coconut 2S, or Wood Fiber HV 2S

Semi-permanent

Slopes1v:2h and steeper, ditches with gradients of 4 percent or less, flow velocities less than 1.7 m/sec. (5.5 feet/sec.), flow depth 75 mm (3 inches) or less.

5 Straw/Coconut 2S Semi-permanent

Ditch bottoms with gradients of 5 percent and less, flow velocities less than 1.8 m/sec. (6 feet/sec.), and under 100 mm (4 inches) flow depth, water course banks within the normal flow elevation.

6 Straw/Coconut 3S, or Wood Fiber 3S

Permanent Ditch bottoms with gradients of 6 percent and less, flow velocities less than 2 m/sec. (6.5 feet/sec.), and under 150 mm (6 inches) flow depth.

7 Coconut 3S, or Wood Fiber 3S

Permanent Ditch bottoms with gradients of 7 percent and less, flow velocities less than 2.1 m/sec. (7 feet/sec.), and under 150 mm (6 inches) flow depth.

Material Type Abbreviations: 0S – No netting, stitching only 1S – Netting on one side 2S – Netting on two sides 3S – More than 2 nettings forming a three dimensional matrix RD – Rapidly degradable netting and stitching NT – No thread/stitching HV – High velocity

22

3)b) Compost Blankets The use of compost for various types of erosion control and accelerated revegetation practices has advanced substantially in recent years. Compost has several key characteristics that are substantially beneficial for accelerated revegetation of disturbed areas along the North Shore that have little topsoil, relatively infertile subsoils and/or exposed bedrock. Compost provides an excellent seed bed for accelerated revegetation. Compost can retain up to several times its weight in water, helping to eliminate runoff from frequent small rainfall events and biotreat the first flush of runoff from all rainfall events. The organic content of compost retains moisture for extended periods to help accelerate revegetation. Compost can also absorb and biotreat a number of pollutants, including those associated with road and parking area runoff. In 2003, MnDOT, in coordination with the Minnesota Erosion Control Association, other state and local government units and the University of Minnesota, School of Landscape Architecture, conducted a demonstration project along a 3-mile length of Highway 61 near the Fall River in Cook County titled Applying Natural Restoration Techniques to Slope Restoration. This project was funded in part by the Great Lakes Erosion and Sediment Control Task Force of the Great Lakes Commission. This natural restoration techniques demonstration project utilized composted leaves and grass clippings in several ways, as well as direct-seeded woody shrubs, to accelerate revegetation of road ditches along an upgraded portion of Highway 61. Compost blankets were one of the BMPs demonstrated, along with other applications of compost. Compost blankets consisted of a layer of compost several inches thick blown onto finish graded road ditches where very little topsoil was available, the soil was very rocky and/or the road ditches were cut into bedrock. Two different fertilizers were used, at different rates, including an organic-based, slow release mix. A native seed mix and fertilizer was injected into the compost at the time of application. Figure 13 and Figure 14 show applications of compost blankets in two different settings along the demonstration reach. The results of this demonstration project were very favorable. Although the compost application was conducted in October 2003, the compost blanket and other compost BMPs held up well until

Figure 13. Compost Blanket, Highway 61, Cook Co. (2003)

23

and after vegetation was established in 2004. A test area on a steep side slope of the road embankment demonstrated faster and thicker revegetation than an adjacent area using topsoil alone, without a compost blanket. Note that Figure 8 above shows a summer 2006 photo of one of the road ditch areas along Highway 61 where a compost blanket and other compost BMPs were utilized to accelerate revegetation. 3c) Compost Logs Compost logs can be used in various applications, including ditch check dams and chevrons, as previously discussed. Figure 2 above shows compost logs used as check dams in a steep drainageway in the Twin Cities area, while Figures 3, 8 and 13 show, or include, compost log check dams and a chevron in road ditches along Highway 61 in Cook County. Figure 15 shows a drainage way along the North Shore Trail in the Silver Cliff Tunnel area, where compost biologs were used in conjunction with a compost blanket to accelerate revegetation and successfully prevent erosion, in a very aesthetically pleasing setting.

Figure 14. Compost Blanket, Highway 61, Cook Co. (2003)

Figure 15. Compost Logs and Blanket at Silver Cliff (2006)

24

3d) Compost Grout Another application of compost is as grout, such as on rock slopes, in riprap and in gabion baskets. Compost grout provides a medium for water retention, growth and sustainability of vegetation and attendant runoff reduction and water quality improvement (as well as aesthetic enhancement). Figure 16 shows an application of compost grout on a steep rock side slope of a Highway 61 embankment in Cook County. This was another component of the 2003 demonstration project in Cook County. Note that the compost was blown into the voids between rocks. This application has held up well. Another potential application of compost grout is incorporation into rock-filled gabion baskets, such as shown in Figure 17. The location of this gabion basket retaining wall is on the the Gitchi Gammi Bike Trail along the North Shore of Lake Superior. Because this site is located at the head of a small ravine, where there is concentrated runoff from Highway 61, there is potential for erosion of sediment into and through the gabion baskets. Compost grout in this application could help retain sediments, reduce runoff and improve the aesthetics of the site.

Figure 16. Compost Grout of Rock Side Slope (2003)

Figure 17. Compost Grout, Potential Application (2006)

25

The U.S. Composting Council created the Seal of Testing Assurance (STA) Program for compost in 2000, in conjunction with Test Methods for the Examination of Composting and Compost (TMECC). The test methods include physical, chemical and biological tests for nitrogren (N), phosphorus (P), potassium (K), heavy metals, E.coli, salmonella, and other compost characteristics and potential contaminants. Compost that meets the associated standards is awarded the Seal of Testing Assurance. When the Great Lakes Commission grant project Applying Natural Restoration Techniques to Slope Restoration was implemented in 2003, compost was trucked from the Twin Cities to the North Shore to ensure adequate quantity and quality. Since that time, the Western Lake Superior Sanitary District (WLSSD) has become involved with the STA Program and the production of certified compost. As the application of compost for erosion control, bioretention and accelerated revegetation grows in popularity, it is expected that additional certified compost sources may emerge in the Highway 61 corridor along the North Shore of Lake Superior. POTENTIAL RETROFIT LOCATIONS Potential retrofit opportunities and locations were identified via analysis of the information sources outlined above and field investigations during May 2006 through June 2007. These analyses and investigations were conducted by BWSR, in cooperation with MnDOT, MPCA, DNR, and SWCD staff within the Highway 61 corridor along the North Shore to identify drainage situations and locations presenting opportunities for runoff energy dissipation, settling, infiltration and/or biotreatment prior to discharge into North Shore streams and Lake Superior. Appendix C – Potential Retrofit Sites in the Highway 61 Corridor – North Shore Retrofit Identification Project includes a list of potential retrofit locations along the North Shore and the Highway 61 corridor from Duluth to northeast of Grand Marias and associated maps to help identify these locations. A number of locations for potential retrofits were identified in each of the three counties in the project area. This list identifies retrofit types to fit the need of the particular water quality problem and/or opportunity at each specific location. Generally, the potential retrofits identified are relatively low-cost practices that could be implemented in conjunction with maintenance and improvement of existing infrastructure. Many of these practices could also be utilized as new construction BMPs. OVERVIEW OF CONSTRUCTION STORMWATER PERMIT REQUIREMENTS The U.S. EPA Nonpoint Pollution Discharge Elimination System (NPDES) construction stormwater management requirements are administered by the Minnesota Pollution Control Agency. Owners and operators of construction activity disturbing 1 acre or more of land need to obtain an NPDES/SDS stormwater permit. Owners and operators of construction activity disturbing less than 1 acre, but that are within a larger common plan of development or sale that disturbs 1 acre or more, must also obtain permit coverage. Applicable guidance and the permit form can be found at: http://www.pca.state.mn.us/water/stormwater/index.html. An updated permit took effect on August 1, 2008. The Construction Stormwater Permit requires the development and implementation of a Stormwater Pollution Prevention Plan (SWPPP). All exposed areas must be stabilized no later than 14 days after construction activity in that portion of the site where work has temporarily of permanently ceased. A variety of BMPs are recommended for temporary and final stabilization,

26

including specific design, inspection and maintenance requirements. Final stabilization includes establishing a uniform perennial vegetative cover over 70% of pervious surface areas. Additional BMPs and enhanced runoff controls are required for discharges to special waters, which include trout streams and Lake Superior. A special waters search tool is available at: http://www.pca.state.mn.us/water/stormwater/stormwater-c.html#specialwaters. There are specific requirements for projects located within 1 mile of, and have stormwater runoff to, impaired waters, where the identified pollutant(s) or stressor(s) are phosphorus, turbidity, dissolved oxygen, or biotic impairment. A list of impaired waters is available at: http://www.pca.state.mn.us/water/tmdl. Retrofit BMPs can be part of a SWPPP for a project that involves 1 acre or more of soil disturbance within existing development, such as improvement of transportation and/or stormwater management infrastructure. The updated Construction Stormwater Permit requirements include an applicable training requirement for individuals who prepare SWPPPs, oversee implementation of SWPPPs and perform inspections required by the permit, or perform or supervise the installation, maintenance or repair of project BMPs. As indicated previously in this report, many of the BMPs recommended by this retrofit identification project are applicable for both existing and new development in the North Shore area of Lake Superior. CONCLUSIONS The Highway 61 corridor along the North Shore of Lake Superior has 3 key natural characteristics, and land use characteristics along Lake Superior, that necessitate extra attention to protect water resources. These characteristics were driving forces for this project. Applicable demonstration projects in the North Shore area, and elsewhere in Minnesota, were sources of increasing knowledge about applicable BMPs for the Highway 61 corridor along the North Shore. This study and report investigated applicable retrofit BMP types, as well as locations within the Highway 61 corridor along the North Shore having opportunities for implementation of these BMPs. Three categories of applicable retrofit BMPs were identified, including:

1) Enhanced Runoff Velocity Control, Detention and Biotreatment 2) Stormwater Inlet and Culvert Filters 3) Accelerated Revegetation.

Within these general categories are a number of specific BMPs that are recommended. Some of these are familiar BMPs that have application as retrofits during repair and improvement of transportation infrastructure and stormwater conveyance systems. The recommended BMPs that are relatively new to the area include various bioretention practices, storm drain inlet filters and various uses of compost for accelerated revegetation and erosion control. Projects to date along the North Shore that have demonstrated the use of compost for these purposes have been very successful. It is recommended that township, county and state transportation authorities, as well as cities, other government units and private individuals, pursue opportunities for implementation of retrofit BMPs to protect and restore the sensitive water quality of the unique North Shore and Lake Superior.

Appendix A North Shore Retrofit Identification Project

Summary of Pertinent Water Quality and Related Information for North Shore Rivers and Creeks

1

River or Creek Impaired Use (303 d list) – TMDL timeline

Fish Passage Problems (MN DNR

Survey 2004)

Active Watershed Group or Project

Recent Assessment / Trend (MPCA 2002)

Local Concerns and

Recommendations

County / State Work Planned for Hwy. 61

or Adjacent

Lester River Aquatic life/turbidity – 2006 - 2011

SWCD forest stewardship project

• NPS pollution and eutrophication

• ↓ water quality since 1970s

Watershed Forest Stewardship Project – South St. Louis SWCD plan

-Lester River bridge restoration 2009 -Condos being built on stream edge just upstream of 61

Talmadge River

Aquatic life/Low oxygen & Turbidity – 2005 - 2011

Significant impediment – control structures below culvert most significant barrier

• ↑ NPS pollution and eutrophication


• rainbow trout population remaining stable


McQuade harbor project nearby on Scenic Hwy 61 (will increase impervious surface at this location)

French River Aquatic life/turbidity – 2005 - 2011




Schmidt Creek



Sucker River Aquatic life/turbidity 2015 - 2020

Significant impediment – maintenance of baffle system in culvert would improve fish passage

Watershed project completed in 2006



• rainbow trout population remaining stable




2



Survey 2004)



Local Concerns and

Recommendations


or Adjacent

Knife River Aquatic life/ pH and turbidity Aquatic consumption/mercury in water column 2002-2007

Lots of forest stewardship planning in watershed, TMDL underway



Watershed Forest Stewardship Project – South St. Louis and Lake SWCD plans

Hawk Hill Road just out of Knife River – Cross pipe with potential for doing sediment ponds – excavators will be there Summer 2007

Skunk Creek Two Harbors, Lake Co. and SWCD doing various projects


Two Harbors Stormwater Management Plan intent to address streambank erosion with GLC grant (done). Lake SWCD High Priority Erosion and Sedimentation area

Br under DM&IRR to .6 mi. No, in Two Harbors, 2007

Flood Bay, unnamed Creek

Stewart River • ↓ water quality since 1970s

Lake SWCD High Priority Erosion and Sedimentation area

Highway reconstruction Stewart River to Silver Cliff - 2021

Silver Creek Significant impediment – low water depth and velocity barriers


Gooseberry • ↓ water quality since 1970s

.4 Mi S of State Park RD to CSAH 5 LT,



3



Survey 2004)



Local Concerns and

Recommendations


or Adjacent

River Thick overlay 2009 Split Rock River


Reconstructions: ¼ Mi. N. of Split Rock R. to Chapins, Bridge 2010, Gooseberry to ¼ mile north of Split Rock 2018.

Beaver River Aquatic life/ pH and turbidity, Aquatic consumption/mercury in water column – 2005 - 2011


Beaver Bay Comprehensive Land Use Plan – clarify vegetation management requirements; Lake SWCD High Priority Erosion and Sedimentation area (East Branch)

Possibly constructing new Co. Road on Co. Road 4 - 1000’ off Hwy 61(with Scenic Byways grant, date unknown) Reconstruction Beaver Bay to Silver Bay 2015

Baptism River • ↓ water quality since 1970s

Paint bridge 2009; potentially updating rest area and parking lot 2016

Manitou River


New concrete culverts along Co. Rd 6, 2007; Co. Rd. 6 reclaim and overlay, reshoulder 2007; Reconstruction - 3.3 mi. North of Little Marais to 1.75 mi. north of Little Marais 2020

Caribou River • ↓ water quality since 1970s

Reconstruction - 1.75 Mi. north of Little



4



Survey 2004)



Local Concerns and

Recommendations


or Adjacent

Marais to Cook county line 2022; reconstruction - county line to 4.1 mi. north of county line 2024

Cross River • ↓ water quality since 1970s

Reconstruction 4.1 miles north of county line to Schroeder Bridge #6202 2020; Cross River Wayside rest 2024

Temperance River


Reconstruction - Schroeder to Tofte and Temperance River bridge 2021; RC in Tofte 2017

Onion River Significant impediment - low water depth and velocity barriers, low priority due to upstream habitat


Reconstruction at Onion River to Co. Rd. 34, two bridges, and Onion River Pedestrian/Bike Trail, MNDOT 2009

Poplar River Aquatic life/ pH and turbidity, Aquatic consumption/mercury in water column – 2005 - 2011

TMDL underway, active group


• rainbow trout juvenile population declining (since 1970s)

Reconstruction Co. Rd. 34 to CSAH 4 2018; CSAH 4 to 1 mi. N. of Co. Rd 41 2023; Reconstruct CSAH 4 1 ½ mile up from 61 to end at Ski Hill 2008

Cascade River • ↓ water quality since 1970s

Reconstruction 1 mi. N. of Co. Rd. 41 to Cascade River 2022;



5



Survey 2004)



Local Concerns and

Recommendations


or Adjacent

Extend Spruce Creek Bridge #8292 2021; Widen Cascade River Bridge #5132 2021

Village Ditch (east of Grand Marais)

Grand Marais Stormwater Mgmt. Plan 2001/ Cook SWCD Workplan

Reconstruct CSAH 7 through Grand Marais, new storm sewer ,curb and gutter ,sidewalk 2007

Devil Track River

Significant impediment, highest priority


Kimball Creek


Kadunce River


Flute Reed River

Active citizen group may form nonprofit


Cook SWCD 2006 identified erosion sources

Brule River Reservation River

Pigeon River • ↓ water quality since 1970s

Painting Bridge MNDOT 2007; Grand Portage State Park and MN DOT 2008– Creation of Pigeon River Rest area (directly next to Pigeon River)

Appendix B Compilation of Local Government Plans Relevant to the Highway 61 Corridor

North Shore Retrofit Identification Project

1

Priority Concerns Action Items

Local Plan Identified concerns Identified Priorities All Streams in corridor

Impaired Streams

Erosion Control/ Stormwater Management

St. Louis County Water Plan 2001

1. Protect and restore Shore Impact Zone

2. Trout streams 3. Rivers 4. BMP education 5. Storm Water

Management 6. Erosion Control Plans

• Lester • Talmadge • French • Schmidt • Sucker • Knife

• Lester River

• Talmadge River

• French River

• Sucker River

• Knife River

1.minimum shore impact zone is 50 feet, 75 feet for trout streams, plus possible additional standards re: fertilizers, pesticides, and other issues that would result in increased nonpoint pollution to the lake or river. 2. wetland protection levels the highest according to the county wetland plan, only residential development allowed within 300 feet of a trout stream, special bluff standards continue as outlined in county zoning ordinances, trout stream shore impact zones should have priority for erosion control and revegetation efforts. The minimum shore impact zone for trout streams will be 75 feet from the stream bank. 3. if no special plan, then may have bluff standards based on soil conditions and lot area standards reflective of the area 4. make information available to every lake and river property owner 5. Stormwater mgmt. plans should be developed in all communities with direct discharge into trout streams or other high quality waters – based on specific minor watershed 6. communities with above average erosion control issues may develop an erosion control ordinance. SWCD is clearinghouse

Compilation of Local Government Plans Relevant to the Highway 61 Corridor – North Shore Retrofit Identification Project

2



Impaired Streams


City of Duluth development plans (62nd Ave. East to Lakewood Township)

• Potential subdivision development (by John Hovland) on Moose Mountain (off Lester River Road) in commercially zoned area

• Amity Creek • Lester River

• Amity Creek

• Lester River


3



Impaired Streams


City of Duluth Stormwater Pollution Prevention Program 2006

• impacts of storm water discharges on water bodies

• Illicit discharge detection and elimination

• Construction site storm water runoff control

• Post-construction site storm water management in new development and redevelopment

• Develop and implement a public participation program to assist in the implementation of the surface water management plan

• Develop and implement a program that includes ordinances prohibiting illicit sewer connections or discharges (including dumping), creates sewer maps, and offers public education on the hazards of illicit discharges

• Develop, implement, and enforce a program to reduce storm water runoff from construction activities on land disturbances of or more acres

• Develop, implement, and enforce a program that addresses storm water runoff from new development and redevelopment, generally using structural and nonstructural BMPs

• Amity Creek • Lester River

• Amity Creek

• Lester River

• Provide information and education to the public about pollution

• Provide opportunity for public involvement and feedback

• Identify and eliminate illicit connections • Develop construction controls to prevent

erosion and pollution • Development of post construction controls • Internal good housekeeping measure for the

city Go to: http://www.lakesuperiorstreams.org/stormwater/duluth/stormwater_plan.html#PhaseII


4



Impaired Streams


South St. Louis SWCD Annual Plan 2006

• Lake and stream protection

• Combined impacts of development

• Outreach and education

• Forestry • Ground Water • Protection of

Community and Natural Resources

• Agricultural • Wildlife management

• Lester • Talmadge • French • Schmidt • Sucker • Knife

• Lester River

• Talmadge River

• French River

• Sucker River

• Knife River

• Provide technical, educational, and financial assistance to install BMPs

• Provide assistance for Lake Superior shoreline erosion problems

• Review DNR water permits and provide input to help limit negative problems

• Work with St. Louis County on lake classification and protection

• Remain member of Lake Superior Basin PWG to ensure the Basin Plan is implemented

• Implement portions of St. Louis Co. Water Plan • Work on watershed protection and restoration

projects (Miller Creek, Knife River and Sucker River)

• Provide more erosion and sediment control leadership, resources, training

• Become a resource for developers early in process, illustrating how natural resource protection is sustainable for business

• Become a GIS center for community • Continue development of Low Impact

Development Assistance Program or conservation site design

• Restore degraded wetlands and wetland function loss

• Continued watershed-based forest stewardship projects (Knife, Sucker, French, Talmadge, and Lester projects)


5



Impaired Streams


Lakewood Township –upcoming plans for development in the corridor (conversation with Zoning Administrator Brennan Mears 7/06)

Actual Developments • Plumbing shop and

storage facility being built now

• Commercial communication tower going in now

• Lester River • Talmadge

River

• Lester River

• Talmadge River

”Use BMPS described in North Shore Management Plan”, such as: • Utilize BMPs to control post-development

stormwater runoff quantity and quality • Erosion and Sediment Control Plans for

disturbances exceeding 1,000 sq. ft., any shoreland alteration within 50 cubic yards within structure setback area.

• Encourage nodal development


6



Impaired Streams


Duluth Township Comprehensive Lane Use Plan 2002

• Deficiencies in the conditional use permit process

• Potential development pressure increases resulting from the proposed sewer line in the North Shore corridor (10.4% population increase since 1990 vs. 1.2% during previous decade)

• Protecting natural resources

• Maintaining rural character

• Balancing the protection of individual property rights with community needs

• Effects on property taxes

• Sucker River • Little Knife

River • Knife River • West Branch

Knife River • Stanley

Creek • Little Sucker

River • French River • Talmadge

River • Schmidt

Creek

• Knife River

• Talmadge River

• French River

• Identify and prioritize important habitat and natural areas

• Limit or redirect development that puts at risk the carrying capacity of land or watersheds

• Control the effects of development to minimize the risk of water contamination of Lake Superior and it’s tributaries.

• Participate in planning with the county highway department in developing road standards that are in keeping with the rural character of the community

• Preserve the functional integrity of all natural drainage courses from impacts due to increased storm water runoff

• Identify and preserve all significant wetland areas vital to the protection of fisheries and wildlife, and to minimize flooding

• Prevent development along Lake Superior which causes erosion or endangers water quality

• Promote use of site designs in the North Shore corridor that mitigate storm water on site, buffer sensitive areas, limit clearing, and preserve natural features

• Encourage participation by the Township in the larger planning efforts for North Shore corridor activities.

• Establish a threshold for new impervious surfaces within sensitive areas, and allow higher thresholds conditional on acquiring conservation easements within the designated area.


7



Impaired Streams


Two Harbors development plans (from ARDC, Two Harbors planner, 2006)

Actual Developments • Blue Waters Resort

(Burlington Bay area) – 6 condos, pool building and office building, phased in over 10-12 years

• Sale of golf course and development in NE corner for housing

• Harbor Hills • Hidden Springs (on

Skunk Creek) – 18 housing units and 24 townhomes

• HRA housing project in Segog area

• Lighthouse Point- zoned parks and rec, conditional use permit for hotel/restaurant complex on lake

• Skunk Creek • Pete’s Creek • Golf Course

Creek • 3rd street

storm sewer • 6th street

storm sewer • arena

drainage


8



Impaired Streams


Two Harbors Stormwater Mgmt. Plan 2001

• Clay soils with high potential for runoff

• 1.5-23% slopes • capacity of current

system is for 10-25 year storm

• Increasing development in watersheds

• Skunk Creek • Pete’s Creek • Golf Course

Creek • 3rd street

storm sewer • 6th street

storm sewer • arena

drainage

• Evaluate existing and 20 year development plans for contributions to storm water runoff

• City and County develop one Stormwater management ordinance (e.g., Dane Co. WI)

• Street sweeping year round • Creek cleaning • Public education, yard waste pick-up • Maintenance of culverts, catch-basins, ditches,

streets • Repair Bank Erosion: Skunk Creek RR Tracks

(GLC grant?) • Updates to Skunk Creek and channel system to

reduce flooding (increase culvert size and widening creek channels) (pp. 11-12)

• Increase Segog ditch and culverts to 100 year event capacity

• Possible re-routing of Segog ‘creek’ to discharge directly to Lake Superior

• Proposed detention ponds • Run-off diversions (Segog area & creek to Skunk

creek)


9



Impaired Streams


Lake County Water Management Plan 2006 – 2015

• Increased development pressures

• Enforcement of existing land use laws

• Stormwater management

• Wastewater management (non-conforming ISTS, surface and GW contamination, drinking water quality)

• Lake and stream water quality, water quantity and biological integrity

• Erosion control on construction sites, road management, cumulative impacts, shoreline erosion control

• Use of BMPs in development activities and forest mgmt. Activities

• Stormwater management

• Natural resources education on water/land issues

• Support of TMDL research project efforts on north shore streams

• Knife River • Stewart

River • Silver Creek • Gooseberry

River • Skunk Creek • Split Rock

River • Beaver River • Baptism

River • Manitou

River • Caribou

River

• Knife River (in both Lake and St. Louis)

• Beaver River

• Natural Resources education (demonstration forest project, property owner’s resource guide, Earthwork contractor’s workshop

• Work with cities, townships and county on erosion and sediment control measures

• Assist Two Harbors in implementing the Storm Water Management Plan

• Implement components of the Lake Superior Basin Plan that are approved locally

• Field inspect construction sites for compliance with erosion and storm water management controls

• Work with city, township and county departments to ensure they are using sound erosion control measures

• Review city and county ordinances for adequate soil erosion and storm water management provisions and other water quality provisions

• Encourage the development of a set of guidelines to evaluate cumulative impacts of development on water resources

• Develop a fund to assist local units of government and/or organizations with water quality projects related to water plan priorities

• Document existing accomplishment (e-LINK)


10



Impaired Streams


Lake County SWCD Annual Work Plan 2006

• Education and Information

• Agriculture • Forestry • Natural resources

planning • Water quality

• Knife River • Stewart

River • Silver Creek • Gooseberry

River • Skunk Creek • Split Rock

River • Beaver River • Baptism

River • Manitou

River • Caribou

River

• Knife River (in both Lake and St. Louis)

• Beaver River

• Education programs, classroom presentations, regional events, featured articles and news releases, Snow Rules and Rain Gauge programs

• Promote knowledge and use of grazing technology • Forest management projects • Assist in development of Natural Resources

Management Plans • Work cooperatively with Lake County Planning

and LGUs, and LASWCDs, SRF JPB, RC & D Council, LS Basin project

• Wetland Conservation Act • Implement Lake Co. Water Plan

-field inspect construction sites for erosion and sediment control measures -assist Planning & Zoning Dept. and Planning Commission on Land Use Issues -meet with townships to review water quality issues

• High priority erosion and sediment areas include roadside erosion (county, township, and Highway 61)


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Impaired Streams


Cook County SWCD Annual Work Plan 2006

• Improve the water quality of degraded/impaired waters

• Work toward goal of effective stormwater management as standard practice in all county reviewed development proposals.

• Cost share implementation for erosion control

• Cross River • Temperance

River • Onion River • Poplar River • Cascade

River • Devil Track

River • Kimball

Creek • Kadunce

River • Flute Reed

River • Brule River • Reservation

River • Pigeon River

• Poplar River

• Provide support to forestry specialist to identify and contact landowners in Flute Reed watershed re: erosion sources.

• Complete site review of property and propose land management project to landowners.

• Provide technical assistance and cost share for erosion control and septic upgrade projects.

• Track improvements on database. • Training on construction site storm water

pollution prevention plans and NPDES; technical assistance.

• Write Natural Resource Property Owner’s Guide for landowners, realtors and regulators.

• WQ sampling on Lake Superior beaches, inland lakes, and analysis, interpretation and community outreach re: results.

• GIS analysis and strategy paper for restoration and protection.

• Flute Reed River and Colville Creek watershed projects.


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Impaired Streams


Cook County Local Water Management Plan – 2006 Proposed Initiatives (from 2006 – 2012)

• Improve the quality of degraded/impaired waters

• Improve wetland management and focus on greater protection of wetland values and functions

• Increase water quality monitoring of near shore and inland lake waters, especially those with development pressure, fisheries concerns and lakes used for drinking water.

• Reduce undesirable water quality impacts associated with roads and other land activity managed and/or approved by Cook Co.

• Develop septic system management plan for Cook County that eliminates sewage impacts to water quality.

• Effective stormwater management as standard practice in all county reviewed development proposals.

• Cross River • Temperance

River • Onion River • Poplar River • Cascade

River • Devil Track

River • Kimball

Creek • Kadunce

River • Flute Reed

River • Brule River • Reservation

River • Pigeon River

Poplar River • Complete WQ monitoring on Poplar River • Work with BWSR and County WCA tech. panel

to write protocol and establish plan for enforcing WCA.

• Establish prioritized list of waters recommended for volunteer monitoring, distribute list to landowners, contact and instruct volunteers.

• Establish baseline or trend data for several county inland lakes.

• Meet with county highway engineer and staff to write plans and procedures to implement 13 action items*(see appendix)

• Develop a media strategy focused on septic system function and installation.


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Impaired Streams


Grand Marais Stormwater Management Plan 2001

• Clay soils with high potential for runoff

• 1.5-23% slopes • Capacity of current

system is for 25-year storm event

Recommendations not yet completed (in priority order) • #5 West Campground – Repair/ create proper

drainage • Continue gauging streams and measuring rainfall • Continue sampling storm water runoff • East Campground – ditching along northern

side, need to reevaluate with Hwy 61 improvements by MNDOT

• Pave side streets off 8th Ave. West • Village Ditch – fix erosion east of 7th avenue E. • Village ditch – up-size culvert beneath Co. Rd. 7 • Village ditch – repair erosion to S. Side at Hwy

61 crossing • Village ditch – Gunflint/Creechville Road culvert

replacement at start of ditch • Maintain stream channels, storm sewers, and

ditches • Verify SWMM model calibration with new

data – updates to existing model expensive • Install high capacity pump in City Hall pond


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Impaired Streams


North Shore Management Plan 2004

• Coordination of flow of info from Studies to LGUs

• Maintain the natural character of the North Shore as much as possible and minimize soil erosion while allowing for permitted development

All North Shore streams

• Lester River

• Talmadge River

• French River

• Sucker River

• Knife River

• Beaver River

• Poplar River

• Examination of important North Shore land use issues, create workgroup and develop policy and model ordinance/suggestions

• Data collection and coordination (liaison between LGUs)

• Education and information distribution • Utilize BMPs to control post-development

stormwater runoff quantity and quality • Erosion and Sediment Control Plans for

disturbances exceeding 1,000 sq. ft., any shoreland alteration within 50 cubic yards within structure setback area.

• Encourage nodal development • Provides minimum standards for LGUs to adopt

which include: -lot area and lot width -structure setbacks -highway access control -building height -lot coverage -subdivision of property - shoreland zoning standards

Lake Superior Basin Plan 2004

Emerging Local Issues: • Increase in stream

temperature • Development along

the North Shore • Paper companies

and forestry • Stability of

northeastern Minnesota’s resource based economy

• Acknowledge and support the important role LGUs play in the protection of water resources

• The maintenance and protection of high quality watersheds

• Utilization of land use and environmental laws to protect water quality

• • Integrate water resource protection programs into local ordinances

• Provide technical assistance to local land use authorities as needed

• Develop strategies to maintain high quality or un-impacted or high resource value watersheds

• Identify high resource value watersheds • Reduce pollutant loadings • Minimize changes in water quantity and peak

discharge rates • Reduce temperature impacts to cold streams and

lakes


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Impaired Streams


• Directional drilling in Lake Superior

• Reduce storm water impacts on lakes, streams and wetlands

• Develop restoration plans for TMDLs

• Develop management plans to maintain and enhance threatened basin waters

• Protect cold water habitats on the North Shore

• Watersheds will be the principal planning framework for water resource management in the LS basin.

• Use the MN CNP Program as a foundation for basin nonpoint pollution issues

• Develop, promote, and improve environmental education in the LS basin

• Protect physical integrity of stream banks and shoreline areas

• Meet Clean Water Act requirements to complete TMDLs

• Restore waters to state standards • Establish watershed or action plans to prevent

future or continuing degradation of impaired waters

• Prioritize sensitive watersheds through the watershed assessment process and knowledgeable basin partners

• Develop strategies to minimize impacts of future or expected development pressures

• Establish baseline data on priority watersheds • Improve efficiency through collaboration and

geographic targeting of scarce financial and human resources

• Enhance cooperation between adjoining jurisdictions and all levels of government

• Facilitate watershed specific partnerships • Design watershed specific protection and

restoration policies and strategies • Use 53 NOAA/EPA management measure options

as performance standards • Help address conditions placed on federal

approval of the coastal nonpoint program • Raise awareness of cause and effect • Raise awareness of nonpoint source pollution • Raise level of stewardship • Foster coordination and cooperation between

government, nonprofit, and private sector


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MNDOT 6-year Plan / North Shore Plan 2006

1. Onion River – 2009 North end of Tofte (85.57- 88.99)

2. Split Rock River – 2010 (42.82 – 46.16)

• Onion River • Split Rock

River

• Follow construction site stabilization schedule as required by NPDES permit

Cook SWCD 2006 Annual Plan – Goal 5.1, Action Items (1 – 13)

1. Develop an annual road inspection process to review private roads in shoreland zones of lakes and rivers. 2. Improve platted road plan submissions and review suggested improvements; clearly describe, map/diagram the road surface material and

volume/quantity, subbase materials, specific shapes and finished grades of ditches and shoulders, sizes and flow calculations for culverts that show relationship to the hydrology of the project area, etc. Require follow-up review with the developer/contractors on site while projects are in building stage and at completion of project. (Planning & Zoning, Highway, SWCD)

3. Develop plat review process that includes analysis and assessment from hydrologic modeling software. Investigate tools available and usefulness for cumulative effects analysis. (Water Advisory Committee, Water Mgmt. Plan)

4. Require use of forest road BMPs for all driveways and private roads of all types. (Planning & Zoning, Highway, SWCD) 5. Prepare and implement an approved erosion control plan for all new county road construction. (Highway) 6. Investigate and address underlying causes that lead to ditch scraping/cleanouts – e.g., too many fines in surfacing materials or excessive

road washouts/culvert failures. (Highway) 7. Require the use of coarse road surfacing materials on roads, driveways and access routes where ditches drain directly into surface waters.

(Planning & Zoning, Highway, SWCD) 8. Advocate for a comprehensive Cook County Road Plan. (Commissioners) 9. Reduce erosion and runoff impacts to lake waters at county managed boat landings. Work with DNR technical staff to improve

landings/accesses within 5 years. 10. Review current county operations and maintenance procedures related to pollution prevention, revise as necessary, and implement

procedures to reduce pollutant loading in surface run-off. (Highway) 11. Develop and implement run-off pollution controls for existing road systems to reduce pollutant concentrations and volumes. (Highway,

SWCD) 12. Establish county road system erosion control and runoff performance standards for county engineer and responsible staff. (Highway,

SWCD) 13. Meet with county highway engineer and staff to write plans and procedures to implement these action items.

Appendix C Potential Retrofit Sites in the Highway 61 Corridor


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Note: Numbers below correspond to locations on Appendix C Maps #1 – #5

Not identified on maps: Canal Park and downtown Duluth – Retrofit storm drains with filter inserts, because there is high pedestrian and vehicular traffic in these areas, which drain directly to the harbor and Lake Superior. Marathon Materials, Dandy Bag and Pig-Drain Inserts are example manufacturers that make bags to filter litter (e.g. cigarette butts, food wrappers, plastic bottles, etc.), oil and other pollutants from runoff entering storm drains. Maintenance includes periodic replacement of insert bags, which can be done at a rate of approximately 3 per hour. The Duluth Downtown Council Green Team is a potential project partner.

1. McQuade Harbor – New parking and lake access area will create new impervious

surface. Promote infiltration practices and storm drain inlet filters.

2. Lakeview Castle Restaurant – has a lot of impervious surface in the parking area that could be changed to pervious surface as a retrofit.

3. East Shilhon Road (GPS 300) – Retrofit for road ditch: seed, erosion control blanket and

fertilizer. Work with county highway department regarding future ditch cleaning, maintenance and revegetation efforts directly after ditch cleaning.

4. Knife River within the Hwy. 61 corridor – Install swales with non-mow mix to be applied

in ditches. This would allow for bioswale / rain garden treatment before discharging to the Knife River. Could install at all outlets to the river, of which there are several. SWCD could provide scenarios for landowners.

5. Ditches in front of Two Harbors businesses (Pizza Hut, Subway, etc.) could have

bioswales and/or rain gardens for treatment of stormwater prior to discharge to Skunk Creek. This could provide a more attractive frontage for the businesses, as well as improve the quality of stormwater runoff.

Not identified on maps: Two Harbors storm drains – MNDOT and city could put urban stormwater filters inside storm drain inlets to catch cigarette butts, trash, sediment, and chemicals.

6. Unnamed creek just southwest of Flood Bay wayside. Recurring maintenance issue for

MNDOT – much debris in stream from old landfill upstream continues to work its way downstream and has to be cleaned out periodically. Retrofit a low-flow bioreactor of wood chips between pervious retaining walls to improve water quality and collect sediment before it gets to the conduit under Hwy. 61. The bioreactor would be designed to overtop during high flows. Flood Bay wetlands are some of the few coastal wetlands along the North Shore.



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7. East Beaver Bay – Construction of the Gitchi-Gami State Trail included the installation of a gabion wall over a ravine. A retrofit here would be to blow seeded compost into gabions to provide biotreatment of runoff from the new trail and Highway 61 prior to entering the ravine.

Not identified on maps: Palisade area – Example of good BMPs installed in conjunction with a new bridge project. Ditch drainage away from toe of embankment, animal crossing space under bridge, velocity and erosion control before runoff in ditches enters the river. Retrofits could include: downstream – rock swale; low-flow compost/wood chip check dam filters or incorporate compost into rock spaces within road ditches. Currently there is some road shoulder erosion caused by runoff from Highway 61. Retrofitting could involve installing a turf reinforcement mat (TRM) or graded filter, possibly in conjunction with chevrons at a low angle from the top of the embankment to the ditch bottom. (Noticed equisetum – a plant indicator species of wet soils with extremely low fertility.)

8. MNDOT truck station at Palisade – will be closed within three years. A retrofit could be

reclamation of the parking lot. The parking lot drains to wetlands, which drain to Lake Superior. There tends to be a lot of salt on the parking lot. A contaminated soil survey likely should be completed there as well.

9. Caribou River – parking lot – could retrofit with a rain garden at the low corner of the lot

with designed outflow channel to the river. Also could add compost chevrons to road banks adjacent to bridge to better control velocity down the embankment from the road surface. Because there is a fish passage issue at this location, a fish ladder / pool and riffle design could be added. On the downstream side of road embankment, could regrade access road to drain away from the river to minimize thermal pollution and/or add compost and vegetation to the stream bank riprap. Seed with vegetation appropriate to the North Shore (e.g. Canada blue joint grass).

10. Sugar Loaf Road – just up from Hwy. 61 at culvert crossing. There has been increasing

development in this area for the past several years. It appears that the culverts may be inadequate and should have better grade design, adjacent erosion control and outlet energy dissipation to avoid erosion of the embankment, ditch bottoms and stream bottom. Appropriately sized riprap with filter, ditch check dams, possibly enhanced with compost mulch and seed are potential retrofits.

11. Temperance River Traders – Retrofits could include compost grouting and seeding of the

rocky ditch areas, with compost log check dams in the steeper areas of the ditch, for water quality and aesthetic improvements. Shoulders along the trail could use a 1 ft. wide gravel transition to the composted ditch to prevent erosion along the edges of the paved trail.

12. Grand Marais – Residents reportedly lament excessive stormwater flow on streets and

associated flooding in some areas. Could construct a series of rain gardens at feasible and



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strategic locations to reduce peak flows, provide biotreatment and increase infiltration that can augment cool groundwater flows to streams. Good examples are Burnsville rain gardens – see on web at: http://www.landandwater.com/features/vol48no5/vol48no5_2.html

13. Creechville Road Stormwater Ponds (Grand Marais) – Retrofit could be to install a

(large) compost-covered gabion basket berm built through the middle of the stormwater ponds (to make cells within the ponds). This could create smaller treatment cells and more effective ponds. Potentially do some strategic replanting of trees to restore some biodiversity around the site.

14. Ditch along Gunflint Trail just above water tower – Install 12-inch diameter compost logs

in areas with steep ditch grades, with the bottom elevation of the next upstream log approximately at the top elevation of the adjacent downstream log, to serve as check dams and for filtering stormwater.

15. Pincushion Mountain Parking Lot – Install flume at east end to prevent erosion. Install a

living engineered swale (turf reinforcement mat), then seed with tall-grass prairie mix, which is better than rip-rap because roots reinforce the soil. Use signs to demonstrate BMPs.

16. Cook County Highway Department – Mixed salt and gravel pile open, with runoff into

ditch – MNDOT and County share the facility. A retrofit could be an enclosed facility, with runoff control and biotreatment.

17. Village Creek/ditch east of Grand Marais – Needs energy dissipation and streambank

stabilization downstream of Highway 61. Plans are reportedly already in process. 18. Devil Track River – Fish passage problem. DNR has identified this as a high priority.

There is also some natural bank erosion impacting mature trees on private property immediately north of Hwy. 61. Streambank stabilization and fish passage design with natural materials are potential retrofit BMPs.

19. County Road 14 dead end at Lake Superior – Abandoned asphalt road along Paradise

Beach should be removed, because it’s washing into Lake Superior bits at a time. Stabilize with natural erosion resistant materials.

20. County Road 14 above Highway 61 – Typical ditch erosion from high water flows and/or

cleaning. It appears that the O/A horizons were scraped away. The potential retrofit here is to replace topsoil, use erosion control blanket, seed and fertilizer, and possibly compost logs or other erosion control practices, to accelerate ditch healing.



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Not identified on maps: There are numerous small parking areas or pull-offs along Highway 61 and Scenic Highway 61 between Duluth and Grand Portage. Many of these parking areas drain directly to rivers and/or directly to Lake Superior. Discharge into rain gardens, use of storm drain filters and/or use of porous pavement to increase infiltration are potential retrofits for these sites to protect and improve water quality. These sites also provide great opportunity for demonstrations and public awareness of these types of BMPs.

Parking Area Identification

Highway 61 Milepost Number

Primary Users

When Open

Lester River Wayside 4.9 Fisherpersons, Tourists Year Round Lester River Info Booth 5.0 Tourists Spring to Fall

Gitchi Gammi Park 5.1 Locals, Tourists Spring to Fall Weigh Station 8.1 Truckers, MnDOT Year Round

Country View Way 8.5 Car Poolers Year Round French River

Historical Marker 11.7 Tourists Spring to Fall

Knife River Rest Area 18.2 Tourists Spring to Fall Floodbay Wayside 27.5 Tourists Spring to fall Old Betty’s Pies

Parking Lot 28.4 Customers Year Round

Stewart River Parking Lot

28.5 Fisherpersons, Tourists Spring to Fall

Silver Cliff Tunnel Service Road

30.3 Locals, Tourists, MnDOT

Year Round

Sliver Cliff Overlook 31.1 Tourists Year Round Lafayette Tunnel

Service Road 34.8 MnDOT Year Round

Gooseberry Falls Visitor Center

39.3 Tourists Year Round

Twin Points Water Access

42.0 Fisherpersons, Tourists Spring to Fall

Split Rock River Wayside 43.3 Tourists Year Round Split Rock Overlook 45.2 Tourists Year Round

Pine Bay Loop Frontage Road

48.2 Locals Year Round



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Highway 61 Milepost Number

Primary Users When Open

Beaver Bay Sports 52.1 Customers Year Round Second Hand Rose

Flea Market 52.1 Customers Spring to Fall

Palisade Head Parking Lot

57.1 Tourist Year Round

Baptism River Rest Area 58.6 Tourists & Truckers Year Round Spirit of Gitche Gumee

Parking Lot 63.6 Customers` Year Round

Eagles Nest Gifts Parking Lot

65.2 Customers Year Round

Caribou River Wayside 70.7 Tourists Year Round Satellites Country Inn 72.0 School bus turn around Spring to Fall

Schroeder Bakery 78.9 Customers Year Round Cross River Rest Area 78.9 Tourists Spring to Fall Cross River Rest Area 79.0 Tourists Spring to Fall Cross River Rest Area 79.1 Tourists Spring to Fall

Temperance River Wayside


Temperance River Wayside


CoHo Café Parking Lot 82.8 Customers Year Round Tofte Rest Area 85.1 Tourists Year Round

Ray Berglund Memorial Wayside

86.5 Tourists Spring to Fall

Rollin Creek Road 87.7 to 88.5 Locals Year Round Clearview Frontage Road 91.8 to 92 Locals Year Round

Cascade Park Wayside 99.9 Tourists Year Round Rex Green Historic Marker 104.1 Tourists Spring to Fall

Cut Face Rest Area 104.5 Tourists Spring to Fall Downtown Grand Marias 109.2 to 110.2 Locals, Tourists Year Round Kadunce River Wayside 118.9 Tourists Year Round



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Highway 61 Milepost

Primary Users When Open

Rest Area 122.9 Tourists Spring to Fall Overlook 137.1 Tourists Year Round

Grand Portage Bay Rest Area & Info

146.0 Tourists Spring to Fall

Mt. Josephine Wayside 146.9 Tourists Year Round Mt. Josephine

Scenic Overlook 147.5 Tourists Spring to Fall

Mt. Josephine Scenic Overlook


highway 61 stormwater natural drainage and retrofit identification project (306-10-07)

Documents