A number of devices treat stormwater by using infiltration to remove pollutants and to recharge or replenish the ground water. Infiltration devices include porous pavements, wetland areas, rain gardens, infiltration basins, infiltration trenches and dry wells (sumps). Some infiltration devices effectively remove pollutants through binding onto soil particles, and by biological and chemical conversion in the soil. These systems, with long detention times, natural vegetation or grass bottoms, enhance pollutant removal by allowing increased time for settling. Moreover, the vegetation increases settling and adsorption of both sediment and pollutants. Although infiltration is a simple concept, infiltration devices must be carefully designed and maintained if they are to work properly.
Properly designed infiltration devices can closely reproduce the water balance that existed prior to development, providing ground water recharge, control of peak flows from stormwater, and protection of streambanks and surface soils from erosion due to high flows. A significant advantage of infiltration is that, in areas with a high percentage of impervious surfaces, infiltration is one of the few means to provide significant groundwater recharge. Because much of the Allen's Creekshed resides within an urbanized area with high levels of impervious surfaces, infiltration offers distinct benefits for groundwater recharge and pollutant removal.
III. Objectives and Strategies
· Improve the water quality of Allen’s Creek, minimally to a level that meets all appropriate Designated Uses of the State of Michigan in accordance with the Clean Water Act of 1972.
· Reduce the water volumes, velocities, delivery rates and peak discharges into the Allen's Creek during rain events, to reduce pollutant runoff and the risk of flooding, soil erosion, streambed erosion and ecological destruction in the creekshed.
· Improve ground water recharge and infiltration.
· Restore and enhance Allen’s Creek as a natural amenity by preserving and reviving the natural features of the creekshed, especially ravines, wetlands, woodlands, greenways and open stretches of the creek.
B. Strategies to Achieve these Objectives
· Engage major stakeholders.
· Quantify conditions of the Allen’s Creek Watershed.
· Promote the review, development, compliance and enforcement of policies that protect the watershed.
· Promote stakeholder education and participation.
· Promote innovative programs to resolve issues of concern in the watershed.
IV. Background on Allen’s Creek and its Watershed
Allen’s Creek is a tributary of the Huron River. The Huron River Watershed encompasses approximately 908 square miles in parts of seven counties (Oakland, Livingston, Ingham, Jackson, Washtenaw, Wayne, and Monroe), running from the Huron Swamp in Oakland County and discharging into Western Lake Erie. The river is used for recreation, drinking water and power generation by the roughly one-half million residents of the watershed, and the watershed contains two-thirds of southeast Michigan's public recreational lands. More than 80% of residents in Southeast Michigan rely on surface water, including the Huron River, as a primary source of drinking water. Over 37 miles of the river and three tributaries have been designated Country Scenic Rivers by the Department of Natural Resources under the State's Natural Rivers Act, the only such designation for a river in central western Michigan.
Allen's Creek's catchment basin, or creekshed, encompasses 5.65 square miles, and is located entirely within the City of Ann Arbor boundaries. The length of the creek system is nearly 12 miles, and flows through the west and southwest sections of Ann Arbor, including much of the central and south campuses of the University of Michigan. The watershed ranges in elevation from 770 to 1020 feet, and receives approximately 30 inches of precipitation annually. Soils in the creekshed include impervious clay soils and pervious sandy soils (Figure 3 on page 49).
The main stem of Allen's Creek begins west of Pioneer High School, runs roughly parallel to Scio Church Road to South Main Street, then meanders through the University of Michigan Golf Course. After crossing under Stadium Boulevard east of Crisler Arena, the creek flows northward to the Huron River. Following the route of the Ann Arbor Railroad, the watercourse passes Fingerle Lumber, crosses South Main Street near the intersection with West Madison Street, flows along the western edge of downtown and the eastern edge of the Old West Side neighborhood, and crosses West Huron Street. The main stem then arches to the northeast between First Street and Chapin Street, crosses Felch Street just east of Spring Street, crosses Summitt at Wildt Street, and courses one block along Wildt Street before crossing North Main Street near Sunset Road, entering the Huron River just downstream of the Argo Pond Dam.
Three primary branches extend westward from the main stem: West Park-Miller Branch, Murray-Washington Branch, and Eberwhite Branch (Figure 1on page 47).
The majority of the creek is enclosed in a stormwater pipe, although several open sections remain. These open sections of the Allen's Creek include stretches that run through Eberwhite Woods and run directly north of Liberty Street between Thaler Street and Virginia Park on the west side of Ann Arbor. The Allen's Creek is a legally established drain under the Michigan Drain Code (56 PA 40), maintained through the Office of the elected Washtenaw County Drain Commissioner and the Utilities Department of the City of Ann Arbor.
B. History of the Creekshed
Allen’s Creek, named in 1824 after Ann Arbor co-founder John Allen, helped define the city's identity through the city's first century. John Allen and Elisha Rumsey set up their camp along the creek to have ready access to a water source, near what is now the corner of First and Huron Streets. As the century progressed, industries that required water located near the creek: a flour mill, tanneries, a foundry, and breweries. Along with the presence of these industries, the flat topography of the Allen’s Creek valley led the Ann Arbor Railroad, in 1878, to locate its tracks parallel to the creek.
By century's end the city had become industrialized, and the water quality and biotic community of the creek had declined. With the development through the early twentieth century of what is now Ann Arbor's Old West Side neighborhood, more sources of pollution to the creek emerged, such as sewage from outhouses. A masonry arch enclosed the main stretch of the creek in 1926 and the lower segments of the main branches were enclosed shortly thereafter. Many masonry arches and bridges were simply buried and may have historical potential.
Development has added impervious surfaces, such as rooftops, driveways, roads and sidewalks. Eventually, increased levels of imperviousness contributed to major flooding (in 1947 and 1968), as well as to recurrent localized flooding experienced in recent years during moderate or large rainstorms (e.g., in 1998 and 2000). Increased runoff velocities eroded banks of open stream channels, which led to further enclosure projects, such as the Liberty-Glendale project in 1997-98.
The amount of impervious surface in the creekshed negatively correlates with the health of the creek. Impervious surfaces are composed materials that prevent infiltration of water into the soil. These impervious surfaces include building rooftops, pavement surfaces (e.g., roadways, parking lots, driveways and sidewalks), and impaired pervious surfaces (compacted or otherwise altered natural surfaces whose pervious properties have been decreased through human action, e.g., baseball diamonds and typical lawns).
Watershed planners suggest that creeks with more than 25% impervious cover in their catchment basin cannot support a healthy biotic community.[5] Allen’s Creekshed passed this threshold long ago. An analysis conducted by the Huron River Watershed Council indicates that 39.3% of the creekshed was covered by impervious surfaces in 1985. In 1990 the level was essentially unchanged at 39.4%, but the level jumped dramatically to 45.8% by 1995. Increased urbanization, with attendant additions of rooftops, driveways, roadways, parking lots, sidewalks and lawns, have fueled this trend. Current and future land use plans (see Figure 6 on page 52), suggest a continuation of this trend.[6]
Increased volume and velocity of runoff, particularly during storm events, occurs with increase of impervious cover. For every acre of natural meadow converted to paved parking lot, the volume of water runoff is estimated to increase about 16-fold.[7] Moreover, increased imperviousness can dramatically increase peak discharge, causing a sharp increase in the immediate water runoff during or following a rain event.
The eight Designated Uses for all waters of the State of Michigan are: agriculture, navigation, industrial water supply, public water supply at the point of intake, warm water fishery/cold water fishery, other indigenous aquatic life and wildlife, partial human body contact recreation, and total body contact recreation between May 1 and October 31. Due to excess nutrients and unacceptable levels of pathogens, Allen’s Creek fails to meet the designated uses for warm/cold water fishery, other indigenous aquatic life and wildlife, and total human body contact for recreation between May 1 and October 31. The Allen’s Creek is not monitored on a regular basis, and few studies are available to determine the current status of the creek.
1. Non-Point Sources of Pollution
Water runoff from impervious surfaces concentrates pollutants by collecting urban runoff. The runoff is discharged to the Huron River without treatment, unlike what normally occurs with Ann Arbor’s sanitary sewage. Because this water runoff collects pollutants from multiple, widespread sites, it is a major vehicle for delivering non-point sources of pollution to the river.
In the urbanized environment of the Allen's Creek Watershed, human activities generate the vast majority of pollutant deposition onto impervious cover. Vehicle use, landscaping practices (e.g., overuse of fertilizers, application of pesticides, raking leaves into street gutters), soil and stream bank erosion, erosion from construction sites, illicit connections to storm sewers, street and sidewalk de-icing practices, waste from domestic animals, improper outdoor storage of chemicals and littering are human activities that contribute non-point sources of pollution by depositing pollutants onto impervious surfaces.
Pathogens, also critical pollutants for the Huron River, can enter the Allen's Creek as non-point pollution. Untreated human sewage can mix with stormwater when sanitary sewers overflow (surcharge) in wet weather, often because of leaks and cracks in sewage pipes or because of local surface flooding. Additional non-point sources of microbial pollution are animal wastes of pets and wildlife that run off impervious surfaces into the stormwater system.
Another significant source of non-point pollution is the atmosphere. Pollutants in the atmosphere become deposited directly into surface waters or onto impervious surfaces from which they can be carried into the waterways by water runoff. Knowledge is generally lacking about the contribution of atmospheric pollutant deposition to the water quality of the Allen’s Creek. Based on recent studies by the MDEQ and Dr. Gerald Keeler of the University of Michigan, mercury deposition from the atmosphere is a likely candidate for concern. Other studies clearly show that polychlorinated biphenyls (PCBs), dioxins, dibenzofurans and similar halogenated polycyclic compounds are dispersed and deposited by the atmosphere. Polybromominated biphenyls (PBBs) and PCBs are considered toxics of concern in the Michigan Great Lakes region.
According to a report released on May 7, 2001 by the Delta Institute in collaboration with EPA, International Joint Commission (IJC), and Lake Michigan Forum,[8] toxic chemicals and metals — including seven chemicals included in the "dirty dozen" now subject to international phase out under a new United Nations treaty —continue to enter Lake Michigan in dangerous amounts and threaten the health of both humans and the ecosystem.
2. Point Sources of Pollution
Several industrial facilities have the potential to be point sources of pollution to the Allen's Creek. These facilities include the Ann Arbor News, GT Products and the University of Michigan Power Plant, which are regulated by the MDEQ. Other facilities include numerous gas stations, car dealerships and dry cleaning operations. Illicit discharges of pollution into Allen’s Creek have been documented. In the early 1990s, for example, the Washtenaw County Drain Commissioner traced a major oil spill to an automobile dealership on Stadium Boulevard. Several facilities permitted under the National Pollutant Discharge Elimination System (NPDES) are located in Allen’s creekshed. Information on permit parameters can be obtained from the state. A 1984 study from the Offices of the Washtenaw County Health Department and Drain Commissioner,[9] lists businesses with storm drain connections, as well as businesses indirectly involved in the use of petroleum products.
Excess loading of the river system with phosphorous is of particular concern, driving annual algae blooms in the creek and downstream in the Huron River's impoundments. Although phosphorus occurs naturally in the region, its presence in excessive amounts contributes to the formation of algae blooms. The algae blooms, in turn, limit recreation uses and threaten aquatic life and wildlife, which are protected by the federal Clean Water Act. Heavy algae blooms are observed each spring in the open channel of the Murray-Washington Branch of Allen’s Creek that courses through the Liberty-Glendale neighborhood, fouling the air and water.
The Middle Huron Initiative, a voluntary strategy administered by the Huron River Watershed Council, identified the highest concentration of phosphorus in Allen’s Creek compared with any other creek or stream in the Middle Huron region.[10] Water quality monitoring by MDEQ in 1996 indicated that the Allen’s Creek contributed 1,000 pounds of phosphorus annually to the Huron River system, or approximately 1/3 pounds/acre/year. Although highly concentrated in Allen’s Creek, other sub-basins contribute greater quantities of non-point phosphorus (>5% of the total phosphorus load) to the Middle Huron.
In order to meet the limits of the Total Maximum Daily Load allocation (TMDL) and the designated uses established under the Clean Water Act, MDEQ has mandated a 50% reduction of the 1995 phosphorus loads in the middle Huron. Although point and non-point sources contribute to the high phosphorus levels associated with algae blooms, the practice of excessive application of lawn fertilizers has been identified as a principal source of phosphorus in residential stormwater runoff. Runoff from bare soils provides opportunities for phosphorous contamination of the creek, also.
In addition to a high concentration of phosphorus, Allen’s Creek is included on the MDEQ list of waters not attaining water quality standards due to unacceptable levels of pathogens. Unacceptably high concentrations of E. coli were measured at the University of Michigan golf course (Washtenaw County Department of Environmental Health, 1995). Untreated runoff from the golf course containing waste from wild and domestic animals is the suspected source for the presence of microorganisms (MDEQ, 1999). However, localized basement flooding of sanitary waste mixed with stormwater has occurred in the Allen's Creek watershed in recent years: on Dartmoor Street in 1998 and 2000 and in the woodland directly west of Virginia Park in 2000. This indicates that sanitary sewage does mix with stormwater and suggests the possibility that human sewage may contribute to pathogen contamination in the Allen’s Creek.
Data on pollutants other than phosphorous and bacteria are generally lacking. Although water quality studies of the Allen’s Creek were conducted by the U.S. EPA in the 1980s under the National Urban Runoff Program (NURP) and the MDEQ as part of its development of the Total Maximum Daily Load (TMDL) allocation for the Middle Huron River in the middle 1990s, details on the results of these studies have not been successfully obtained. Dr. Michael Wiley from the University of Michigan measured markedly high conductivity in an open section of the Murray-Washington Branch of Allen’s Creek (in the Liberty/Glendale Street area), suggesting heavy contamination of metals (personal communication to R. Loch-Caruso).
C. Water Volume and Dynamics
Minimal flow monitoring data exist for the system. The engineering firm of Black & Veatch conducted a flow-monitoring program in 1994 for the City of Ann Arbor Storm Water Master Plan. However, during the study period the storms were low intensity and low volume. Black & Veatch reported that the flow monitoring data were not used in the development and calibration of the computer stormwater model because the lack of data from high intensity and duration storms prevented adequate calibration of results in their model.
Located on the 195 acres of the floodplain of the Allen’s Creek are more than 650 parcels that include land uses ranging from single family residential to commercial and industrial operations. To date, stormwater management in the Allen's Creek Watershed has entailed conventional engineering flood control measures, that is, conveying stormwater via paved gutters and channels into stormwater pipes that deliver the water, untreated, to the Huron River. However, these conventional stormwater management techniques also exacerbate stormwater problems in the creekshed because they increase the rate and volume of water delivery, transferring and increasing stormwater impacts downstream. Increased urbanization of the Allen's Creek Watershed, with an estimated increase of impervious cover to 45.8% by 1995, is associated with increased occurrences of flooding. The system has the capacity to convey a storm in the range of the 1.5-year, 24-hour frequency storm.
A study by Black & Veatch[11] documented that the Allen’s Creekshed experiences the most severe flooding in the city. This study supported results of a survey on flooding of Ann Arbor residents conducted in 1994 by the Ann Arbor Water Utilities Department. Within the creekshed, 1,682 questionnaires were mailed and 517 responses were received. Major problems from flooding were reported by 136 respondents. A detailed summarization of these survey results is included in Appendix B.
Increased occurrences of flooding indicate that the conveyance system is unable to handle current runoff in the watershed. Basement flooding of homes occurs frequently in the Murray-Mulholland area during or after rains. In recent years and on numerous occasions, the water pressure has blown off stormwater manhole covers in the Murray-Mulholland area, so that manhole covers in this area are now welded shut. The Fingerle Lumber Company likewise experiences recurrent flooding, as do several buildings and Crisler Arena on the University of Michigan campus. Street flooding in recent years at Kingsley and First Streets was so extreme that a woman had to be rescued from her car trapped in several feet of water. Elder Street, an unpaved street off Eberwhite Boulevard, experiences frequent street flooding, also. Additionally, heavy rains in 1998 and 2000 produced basement flooding of homes on Dartmoor Street in the Eberwhite neighborhood that contained mixed sewage and stormwater. Mixed stormwater and sewage also flooded the basement of the Men’s Shelter on Huron Street (near Chapin) in 2000.
In addition to inundating streets and basements, frequent stormwater flooding is destroying a several acre wooded area, a neighborhood commons park, immediately west of Virginia Park in the Liberty-Glendale area, just downstream of the section of Allen’s Creek that was enclosed in 1997-98. Because this wooded area experiences flooding repetitively and frequently, the trees are dying at an accelerated rate. During a significant rain event in 2000 that measured 3.75 inches of rain overnight in a local rain gauge, staining of the vegetation in this woods, measurement by a neighbor and photographs after the rain event indicated that the floodwaters reached 6 feet. Although the manhole covers to the sanitary sewers are elevated in this woodland, flood debris on the top of the sanitary sewers indicated that stormwater covered the manhole nearest Virginia Park and entered the sanitary sewer system at this point. Evaluations by the Washtenaw County Drain Office and the Department of Environment and Infrastructure confirmed that sewage and stormwater likely mixed and contaminated this commons park area (personal communication to V. Caruso).
Minimal flow monitoring data exist for the system. The engineering firm of Black & Veatch conducted a flow-monitoring program in 1994 for the City of Ann Arbor Storm Water Master Plan. However, during the study period, the storms were low intensity and low volume. Black & Veatch reported that the flow monitoring data were not used in the development and calibration of the computer stormwater model because the lack of data from high intensity and duration storms prevented adequate calibration of results in their model.
No studies on the ecological health of the open sections of the Allen’s Creek have been located.
The Allen’s Creek Watershed is experiencing increased erosion of land surfaces and stream banks. To counter severe erosion to the stream banks of one of the few open stretches of the creek, a recent project in 1997-98 enclosed a short stretch in the Liberty-Glendale area (at the cost of nearly $500,000 to the city). Erosion continues in the remaining open stretches in this area, evidenced by gouging and widening of the channel and erosion of the stream banks. Also, erosion is exposing the cement bulkhead of the entrance to the enclosed section of the channel just west of Virginia Park. Similar indications of severe erosion exist just upstream of the Liberty-Glendale project in the open channel that runs through the property of the Westwood Apartments on Liberty Street. At this site, the eroding channel banks are toppling large and small trees across and into the stream. Soil erosion along sidewalks and the street are evident on West Liberty Street between Virginia Avenue and West Stadium Boulevard. Elder Street, off of Eberwhite Boulevard, experiences significant erosion from storm events. Erosion along the open channels of Eberwhite Woods is severe, as well, with evidence of gouging and widening of channels and erosion of stream banks.
In addition to deterioration of natural features and structures, erosion contributes to the degradation of the water quality of the Allen’s Creek. Soil erosion is a significant source of phosphorous, and phosphorous is identified as a critical pollutant of concern (see previous section on Water Quality). Moreover, soil carried into the waterway increases sedimentation and, thereby destroys aquatic habitats.
Although the majority of the waterways in the Allen's Creek watershed are enclosed, some open stretches remain. Many of these streams are considered amenities valued by neighboring residents. A portion of the upper reaches of Allen’s Creek main stem is open through the University of Michigan Golf Course at the corner of Stadium Boulevard and South Main Street. On the west side of Ann Arbor, open channels of tributaries of the Murray-Washington Branch course through the Westside Apartments on Liberty Street, through the private park greenspaces of the Glendale and Liberty Knoll Subdivisions between Glendale Circle and Liberty Street and across the southern boundary of West Park. In addition, open stretches of the Eberwhite Branch course through the Eberwhite Woods, the largest woodland/greenspace on Ann Arbor’s west side.
All open stretches of the Allen's Creek on Ann Arbor's west side shows signs of extreme stress from high water volume, velocity, rate of delivery and peak discharge. Perhaps most evident is the erosion of the stream beds and banks, causing channel widening, ravine degradation and the death of trees along the banks. Closer examination shows the deterioration of the ecological health of the stream, with little evidence of establishment of biological communities. Although the open stretches of the Allen's Creek may not be able to support significant aquatic life, they nonetheless serve as important water sources for other wildlife such as birds and small mammals. Furthermore, they are valued by neighboring residents as a recreational amenity. These open channels provide opportunities for reducing water volumes, velocities and rates of delivery to the main drain system by providing pervious surfaces and opportunities for overflow. In addition, they improve water quality by increasing aeration and allowing absorption and filtration of excess nutrients and contaminants. Preserving and enhancing these open stretches of the Allen's Creek can protect natural features within the city while providing benefits for water quality and stormwater management.
Moreover, many sections of the Allen's Creek that are enclosed course through ravines and beneath wooded areas that are valued parks and greenspaces for neighborhoods. On Ann Arbor's westside, for example, a section of the Murray-Washington Branch lies beneath the Liberty-Knoll Commons private park and Virginia Park. Sections of the West Miller Branch are buried in the ravine of the Wildwood Park and in wooded areas just north of West Huron Street. Replacing the current enclosed system with larger diameter pipes, to handle the high water volumes, velocities and peak discharges now experienced, would result in the loss of significant, valued natural features, including trees, ravines and woodlands. In fact there has already been natural feature destruction where sanitary sewers have been upgraded on the west side of Ann Arbor.
H. Regulatory Protections
Activities that impact the Allen's Creek Watershed are regulated by various agencies on the local, state and federal levels. Some of the more salient regulations are described here and are listed in Appendix C.
The Allen's Creek system is an established Chapter 20 County Drain, operated and maintained by the elected County Drain Commissioner and administered by the Statutory Drain Board. However, some sections are apparently under the jurisdiction of the City of Ann Arbor.
Allen's Creek is a tributary of the Huron River that courses through, and is contained within, the City of Ann Arbor. Since 1992, cities with populations exceeding 100,000 were required to develop and implement stormwater plans under Phase I of the National Pollutant Discharge Elimination System (NPDES) stormwater regulations. The EPA has promulgated a rule that requires smaller municipalities (with populations less than 100,000), to develop stormwater plans under the so-called "Phase II" rule. Moreover, under this Phase II rule, the EPA and states will develop strategies from which local governments will select those that best suit their needs and objectives.
The national floodplain regulations are minimum standards. The National Flood Insurance Program (NFIP) regulations, in fact, encourage states and local governments to adopt more stringent standards: “Any community may exceed the minimum criteria under this part by adopting more comprehensive flood plain management regulations.” [12] Federal Executive Order No. 11988 prohibits the use of federal funds for construction in the floodway or 100-year floodplain.
Although the state floodplain regulations are stronger than those of many other states, the interpretation and enforcement by MDEQ of the floodway rules promulgated under Part 31 of PA 451 of 1994 may warrant discussion and review. A few states can provide models to Michigan for enhanced floodplain management. For example, Wisconsin's Floodplain Management Program, Chapter NR 116, prohibits residential and commercial occupation on or over a floodway.
Experiences in Allen’s Creek suggest that the permitting process addresses the concern for increased stage that may cause harmful interference, requiring a hydraulic and hydrologic study, for example, but that it may not adequately address the concern for changes in direction of flow. Permitting a structure in the floodway built on piers, for example, avoids an increase in stage but does not address dangers associated with the temporary obstruction of flows in the floodway.
Depending on the specific circumstances of the site (for example, the narrowness of the floodway channel or the steepness of the floodway's gradient), a piered structure in the floodway, or one with fenced enclosures, may cause changes in the direction and levels of flow because of the accumulation of floating debris – tree branches, cars, dumpsters, recycle cans, patio furniture (including umbrellas, tables and chairs), paper, plastic, various objects – that can get caught on or between piers and obstruct the flow of floodwater. Such a structure could thus cause harmful interference.
Local regulations also suffer from some inadequacies. As is the case on the federal level, the city's floodplain regulations are minimal standards. They cover the basic compliance requirements for participation in the NFIP. There are also enforcement issues within the City of Ann Arbor. Recently, the city's Building Board of Appeals (BBA) granted a variance from BOCA requirements to a developer to construct an office building, the first floor of which would be under the 100-year flood level, without wet-proof construction. As part of its NFIP participation agreement, the City of Ann Arbor agreed not to grant variances from BOCA floodproofing requirements. The MDEQ issued a letter of warning to the City of Ann Arbor Building Department, stating, “Continued use of the variance procedure to evade the building code and the NFIP requirements could result in the placing of the City on probation or suspension from the NFIP.” The NFIP restriction against these types of variances has never been incorporated into the criteria by which the BBA evaluates variance requests. Such incorporation may allow the city to avoid the ultimate penalty of suspension from the NFIP.
Recent changes to the Ann Arbor City Ordinance Chapter 63, that specify on-site regulations for water runoff in alignment with the Rules of the County Drain Commissioner's Office, are an example of regulatory protections that benefit the creekshed.
I. Condition of the Enclosed Infrastructure
In its 1997 report, Black & Veatch estimated the cost of a full retrofit of the Allen’s Creek stormwater system to be around $41 million, out of a total cost for a citywide retrofit of almost $98 million.[13] Implementation of this construction would require tree removal and destruction of greenspaces valued by neighborhoods. Even with this significant investment, the critical issue of water quality would not be addressed, however. Consequently, additional costly expenditures would be likely, as the US EPA implements Phase II of the National Pollutant Discharge Elimination System (NPDES) stormwater regulations requiring the City of Ann Arbor to clean up the water before it is discharged into the Huron River. Maintenance and upgrades to the enclosed infrastructure will not abate stream deterioration, and restoration costs are also significant, as evidenced by the recent study of Malletts Creek (estimated at $20 million).
J. List of Allen’s Creek Watershed Maps
The following detailed maps of the Allen's Creek Watershed can be found in Appendix K, starting on page 47:
Allen's Creekshed with elevation, streets and floodplain. (GIS map)
Allen's Creek Creekshed with NPDES premittees (GIS map)
Allen's Creekshed with with future land use (per master plan) (GIS map)
Allen's Creekshed soils (GIS map)
Allen's Creekshed with sub-basins (GIS map)
Allen's Creekshed with natural features and open spaces (GIS map)
Allen's Creek Creekshed with 1995 land use (GIS map)
If gray scale maps appear in the current document, color maps are available and are in select final copies and in the hypertext file.
Recognizing the enormity of the task, the variety of concerns and objectives of stakeholders, the requirements for financial investment and technical assistance, and critical limitations of time, the Strategic Plan outlines an approach to resolving critical concerns in the Allen's Creek Watershed. This is a working plan, designed for immediate action as well as on-going strategic planning.
A. Engage Major Stakeholders
Implementation of improvements to the Allen's Creek Watershed will be greatly facilitated by communication and cooperation among the major stakeholders. Because the watershed is located within the City of Ann Arbor, individuals and organizations that operate within the city are all potential stakeholders. Stakeholders in the Allen's Creek Watershed generally belong in one of five categories: residents, businesses, government organizations, nonprofit organizations and other public organizations.
2. Potential Stakeholders
An alphabetical listing of potential stakeholders can be found in Appendix A on page 30.
Residents of Ann Arbor. All residents of Ann Arbor, whether homeowners or renters, are potential stakeholders because their homes lie within the watershed area. Even if the residences are not adjacent to Allen's Creek waterways or drain systems, homeowners pay taxes to the city, rely on stormwater management and contribute water runoff to the system. Moreover, various human activities throughout the watershed, such as vehicle and land use, can impact the watershed. Resident stakeholders of particular interest are individuals whose homes experience flooding, lie within the floodplain or floodway, lie near open channels of the creek, or are located along wooded areas or ravines through which enclosed sections of the creek traverse. Some, but not all, neighborhoods in Ann Arbor have organized neighborhood groups, and these groups can serve as a mechanism for communicating with resident stakeholders. Some of these identified groups are: Old West Side Association, Old West Side Garden Club, West Park Neighborhood Association, Murray-Mulholland Residents Association, Glendale-Liberty Neighborhood Group, North Central Neighborhood Association, Dover- Parkside Neighborhood Association and Parkside Commons Condominium Association.
Businesses that operate within the City of Ann Arbor. Businesses are potential stakeholders that lie within the watershed area, pay taxes to the city, rely on stormwater management for their operation, and engage in activities that can impact the health of a watershed. Business stakeholders of particular relevance include owners and operators of businesses that experience flooding, lie within the floodplain or floodway, or lie adjacent to enclosed sections of the creek. In addition, businesses in the building trade are important potential stakeholders because development and soil disturbance can significantly impact the watershed. Because the Ann Arbor Railroad and Conrail course through critical areas of the Allen's Creek Watershed, they are particularly relevant potential stakeholders. Some of the stakeholder businesses are organized into associations that can serve as a mechanism for communication. These organizations include the West Stadium Business and Professional Association, Downtown Development Authority and the Chamber of Commerce.
Local, regional, state and federal government organizations. Organizations at all levels of the government are potential stakeholders because they oversee policies and regulations that impact the watershed. Because the Allen's Creek Watershed lies entirely within the City of Ann Arbor, the city government of Ann Arbor is a significant stakeholder. City government offices and organizations of particular interest include the Mayors Office, City Council, Water Utilities Department, Parks and Recreation Department, Planning Commission, Parks Advisory Commission, Building Department, Historic District Commission, and Transportation Department. Regional government organizations of particular interest include Washtenaw County, Urban Area Transportation Study (UTAS) and Southeast Michigan Council of Governments (SEMCOG). Most of the Allen's Creek system is under the jurisdiction of the Washtenaw County Drain Commissioner's Office, making this government organization a significant stakeholder. Various state government organizations that are potential stakeholders include the Department of Environmental Quality, Department of Natural Resources, Department of Transportation, and Bureau of Construction Codes. At the federal level, the U.S. Environmental Protection Agency and the Federal Emergency Management Agency are significant potential stakeholders.
Other public organizations. Several other public organizations are important potential stakeholders in the watershed. The University of Michigan is an important stakeholder, as an educational institution, employer, and the largest single landowner in Ann Arbor. The Huron River Watershed Council, its Middle Huron Initiative, and various watershed groups in southeast Michigan are potential stakeholders that share the common interest of protection of the Huron River watershed. In addition, the Ann Arbor Transportation Authority is a potential stakeholder because of the significant impact of vehicle use and pavement on the watershed. The Ann Arbor Public School system is a potential stakeholder because it is a significant landowner, including sites through which opened and enclosed sections of the Allen's Creek flow. Additionally, science teachers may wish to incorporate study of the watershed in the curriculum.
Non-profit organizations. Various nonprofit organizations have interests in the well being of the Allen's Creek. These include the Huron Valley Group Sierra Club, Potawatomi Land Trust, Ecology Center, Huron Land Use Alliance, and the League of Women Voters.
Allen's Creek Watershed Group. The Allen's Creek Watershed Group is an open, self-selected group of citizens, business owners and operators, government liaison representatives and other public organization representatives, with no attempt to balance representation among the potential stakeholders, that has been meeting regularly to initiate actions to protect the Allen's Creek Watershed. The Allen's Creek Watershed Group has designed the present plan as an initial working plan for the management of the watershed, aiming to provide a rationale and strategy for working with stakeholders to evaluate conditions, identify options, and implement policies and programs to improve the Allen's Creek watershed.
Clearly, there are many potential stakeholders. Moreover, the potential stakeholders are likely to have widely divergent concerns, resources and priorities. This presents significant challenges for designing and implementing specific actions for management of the watershed.
3. Open Meeting with Potential Stakeholders
An open meeting with potential stakeholders will be held for the purpose of communicating the rationale for designing a watershed management plan, a description of the current understanding of the conditions of the watershed, and the identified concerns of the stakeholders. Although concerns identified by the Allen's Creek Watershed Group will be presented, an important aspect of this meeting will be to identify concerns of a broader representation of stakeholders in the watershed. Another important objective of this meeting will be to identify and involve stakeholders with the technical expertise and resources that will be required to develop and implement a more detailed watershed management. This plan must meet the requirements for the Clean Michigan Initiative administered by the Michigan Department of Environmental Quality and the MEDQ requirements of an approval plan.
4. Formation of Steering Committee
A specific outcome of the open meeting with potential stakeholders will be the identification of a lead organization and the formation of a steering committee, the Allen’s Creek Watershed Management Plan Committee. The purpose of the steering committee will be to oversee the implementation of the watershed management plan. Members of the stakeholder group will be invited at the open meeting to serve on the steering committee. Membership of the steering committee will include representatives from each of the major stakeholder categories identified above and, ideally, representatives from each of the significant stakeholder organizations. The lead organization will, ideally, have the staff and resources necessary to organize and oversee implementation of the plan.
5. Continuing Communication with Stakeholders
Although the steering committee will include members of various stakeholder groups, broader communication will enhance the likelihood of success of the watershed management plan. To improve communication, the steering committee meetings will be announced in the newspaper and will be open to the public. Also, the steering committee will submit press releases of newsworthy items to local news groups. Members of the steering committee will be available to speak to various groups of stakeholders. As an important link, a WebSite will be maintained that includes the most current version of the watershed management plan, agendas and minutes of steering committee meetings, data on the conditions of the watershed, and a mechanism for the public to communicate with the steering committee.
6. Identification and Prioritization of Critical Concerns of Stakeholders
Inherently, the identification and prioritization of critical concerns in the Allen's Creek Watershed will be an ongoing process as concerns, data on the watershed, and information on potential interventions are collected and analyzed. The steering committee will be responsible for identifying and prioritizing critical concerns in the ongoing development and implementation of the Allen's Creek Watershed Management Plan.
B. Quantify Conditions of the Allen's Creek Watershed
It is important to establish baseline data and to conduct regular monitoring on a continuing basis of the conditions of the Allen’s Creek. These data will provide the community with the detailed knowledge of the watershed that will improve decision making and afford a mechanism for tracking progress after policy or program implementation.
1. Water Quality Monitoring
Based on past studies by the U.S. EPA and the MDEQ (described earlier), phosphorous and pathogens should be monitored. Additional study should determine whether other pollutants should be monitored. Because Dr. Michael Wiley (University of Michigan) found extremely high conductivity levels in an open channel of the Murray-Washington Branch, metal contamination should be considered.
Data collection should take place at the outlet of Allen’s Creek to the Huron River and at several points along the system. Potential monitoring stations within the creekshed include points where the main branches intersect with the main stem and where major tributaries intersect with main branches. At an even closer level of detail, monitoring and data collection could take place within the 46 drainage sub-areas modeled by Black & Veatch in the 1997 City of Ann Arbor Storm Water Master Plan.[14]
2. Water Volume and Velocity Monitoring
Past efforts to monitor water volumes and flow dynamics (as well as quality) in Allen’s Creek were thwarted because surging within the pipes was so forceful that monitoring equipment was damaged, destroyed or washed away. Nonetheless, some measure of these phenomena is highly desirable to facilitate understanding, evaluate options and appraise the effectiveness of actions. A review of available instrumentation should identify whether new options may allow measurement of water dynamics even under surge conditions. Alternatively, quantification of the occurrence of surges themselves could be used as baseline data by which to measure progress of implemented programs, for example, through the use of tell-tales in drain manholes.
3. Hydrology, Hydraulics and Stormwater Monitoring
Accurate hydrologic, hydraulic and stormwater modeling of Allen’s Creekshed is necessary in order to determine the magnitude of the problem and whether proposed programs would be effective in improving water flow and quality. The modeling of the Allen’s Creek watershed undertaken by Black & Veatch in 1997 was insufficient.[15] Flow monitoring data were not used in the development and calibration of the stormwater model because the data collected were insufficient.
4. Impervious Cover Monitoring
A study by the Huron River Watershed Council analyzed the extent of impervious surface in the Allen’s Creek Watershed. In 1995, the last year included in this analysis, the watershed had 45.8% impervious cover. Because impervious cover has a very significant impact on water quality and water dynamics in the watershed, monitoring changes in impervious surface will provide important information for development and evaluation of watershed policies and programs. It is recommended that impervious surface in the watershed be analyzed on a five-year basis. The goal of reducing impervious surface must be incorporated in any new city ordinances that affect this watershed.
Both soil and stream channel erosion should be monitored. Initial baseline information will need to be obtained because there is currently no database on this, only anecdotal information. A walking tour of the watershed is recommended to collect baseline data on erosion (as well as other concerns). Locations of particular concern can then be noted and monitored on an ongoing basis. Because there are only a few stretches of open channel in the Allen's Creek Watershed, local existing groups will be recruited to monitor nearby channels using a consistent evaluation scheme (to be developed). For example, the Eberwhite Woods Committee and Elementary School could assist with the channels in Eberwhite Woods, and the Glendale-Liberty Neighborhood Group could monitor the channel in that neighborhood.
In addition to erosion, open channels of the Allen's Creek should be monitored for their ecological health. Local groups will be recruited to conduct regular surveys of sentinel aquatic species through the Adopt-a-Stream Program of the Huron River Watershed Council. The occurrence of algae blooms will be noted as an index of excess nutrient contamination.
The City of Ann Arbor Water Utilities Department monitors flooding events. Information on past flooding occurrences will be requested from the Water Utilities Department for the last 15 years, summarized over five-year periods, to obtain baseline information. After initiation of implementation of the watershed management plan, flooding information within the Allen's Creek Watershed will be summarized on an annual basis and made available to the steering committee to facilitate program and policy development and evaluation. This summarization should include details on the type flooding that occurred (e.g., street, basement, mixed stormwater and sewage), and a ranking scheme indicating the severity of flooding.
8. Floodplain Recalculation
In addition, a review and reanalysis of the floodway and floodplain is warranted, given the extensive increase of impervious surfaces that has occurred since the last analysis. The floodplain in the Glendale-Liberty area along the Murray-Washington Branch of the Allen’s Creek was recalculated for a stormwater project in 1997[16]. This calculation put the floodplain at an elevation 1.2 feet higher than the recorded floodplain. Several homes built up to the edge of the floodplain, as calculated at the time of the neighborhood development, now lie within the newly calculated 100-year floodplain. With the significant increase of impervious cover in the watershed, it is likely that the current floodplain is out-of-date in other areas of the watershed.
C. Promote the Review, Development, Compliance and Enforcement of Policies that Protect the Watershed
1. Identify and Inventory Existing Relevant Policies and Regulations
Protection of the watershed depends on public policies and regulations. Public policies and regulations that are relevant to the protection of the watershed will be identified and inventoried. This inventory should be easily accessible to stakeholders, for example on a WebSite (with hyperlinks, if relevant) and by pamphlets. City, county, regional, state and federal policies and regulations will be included in this inventory. Appropriate government offices (stakeholders) will be recruited to assist in this process. The Codes and Ordinances Worksheet developed by the Center for Watershed Protection is one example of a starting point for information and regulations.
2. Inform Stakeholders of Existing Regulations and Policies
Many stakeholders may be unaware of existing regulations and policies that serve to protect the watershed. In this regard, compliance with existing regulations and policies may be enhanced by improved communication among stakeholders, in particular between government agencies, residents and business operators. By improving understanding of how human activities impact the watershed, how the conditions of the watershed impact human society, and public knowledge of existing regulations that protect the watershed, the general public can become a partner with government organizations to promote compliance and enforcement of existing regulations. Inherently, advancement in this area would depend on education strategies outlined in a later section. Additionally, mechanisms should be established to facilitate access of the public to knowledgeable government sources, such as contact information or hyperlinks on a WebSite.
3. Promote Improvements to Public Policies
Public policies and regulations will be reviewed for completeness and adequacy for protection of the watershed. Immediate actions are recommended, as identified below, and additional options for consideration are included in Appendix D on page 34.
Strengthen the city's stormwater runoff regulations. The City of Ann Arbor has recently (June, 2000) improved regulation of stormwater runoff by implementing changes to Chapter 63, the city ordinance that specifies site development. These changes align the city's policies with those of the Rules of the Washtenaw County Drain Commissioner’s Office. These changes were encouraged and are strongly supported by this group.
However, there are areas in the city where street and basement flooding occur every few years. It is recommended that construction projects upstream from these critical areas be required to restrict surface water runoff to higher standards. Specifically, in these critical zones it is recommended that (1) new developments achieve zero stormwater runoff for a 100-year event, (2) construction that replaces or modifies existing structures does not increase surface water runoff and reduces surface water runoff, if possible. In addition, it is recommended that the city develop policies to encourage the use of stormwater as a design amenity.
Strengthen the city's floodplain regulations. As part of a comprehensive watershed management plan, the City of Ann Arbor should address deficiencies in floodplain management regulations. Unless addressed, the presence of impervious surfaces in the floodplain prevents water absorption and detention, increasing the volume and rate of delivery of water to the waterways and thereby exacerbating flooding conditions. Moreover, delivery of pollutants into the waterways is extreme under flooding conditions. Because of deposition of pollutants by human activity onto impervious surfaces in the floodplain and floodway, pollutants are washed into the waterways under flooding conditions, thereby degrading water quality. In addition to issues related to impervious surfaces, structures in the floodplain and floodway contribute to the problem by adding debris to the flood waters and obstructing flow. Threats of economic losses and liability are sufficient to warrant action on this matter.
A basis for addressing the deficiencies in floodplain management regulations has been provided by the Ann Arbor City Council in its April 5, 1999 "Resolution Regarding Enhanced Management of Ann Arbor's Floodplains and Floodways." Prohibition of the construction of new buildings in the floodway or, at least, in areas of the floodway that present special hazards (e.g., a narrow channel or steep gradient) is recommended. Construction of potential or temporary obstructions such as berms, piers, "tight" fences and retaining walls should be prohibited, to protect against potential damming and diversion of flood waters. City policies should be promoted and developed to encourage acquisition and/or retrofit modification of existing structures in the floodplain, to allow the floodplain to function as a water detention, absorption and infiltration area. In addition, revisions to the Building Code are recommended that would require that the lowest finished floor of new construction be at a specified height (one or more feet) above the 100-year floodplain elevation, i.e., something greater than what is now required. The recommended changes have the benefits of improving water quality, and secondarily, of limiting potential liability for the city.
Strengthen the state's floodplain regulations. As part of its revision of the state floodplain regulations, the MDEQ should be encouraged to adopt the Wisconsin standard and prohibit any encroachment in or above the floodway or, minimally, in those portions of the floodway where the channel is narrow and/or the gradient is steep. Additionally, the MDEQ should be encouraged to consider potential debris accumulation and temporary obstruction to flow in its floodplain regulations.
National Floodplain Insurance Program (NFIP) Community Rating System (CRS). Enroll the City of Ann Arbor in the National Floodplain Insurance Program (NFIP) Community Rating System (CRS) and implement the criteria in the CRS to maximize the city's score. This action would improve water quality by allowing the floodplain to function more normally and would provide an added benefit to residents in the form of lower flood insurance premiums.
Support New EPA Stormwater Regulations. Support and quickly adopt the US EPA implementation of improved water quality and water quantity performance standards for municipal stormwater and watersheds.
Revise City policies related to creekshed water quality. Develop city utilities and engineering regulations that incorporate standards and practices sensitive to preservation of natural features of the watershed. Schedule and design leaf collection procedures to reduce runoff into the creek. Remove sand from roadways early the in spring to reduce its runoff. Utilize existing parcels of the Parks Department to reduce runoff and promote water cleansing and ground water recharge.
4. Promote Enforcement of Existing Regulations
If there is evidence of poor compliance with current regulations, the procedures of those government offices charged with the responsibility of overseeing those regulations should be reviewed. The outcome of such a review should include recommendations for changes in procedures and/or policies that aim to improve compliance. Penalties or fines, in particular, should be reviewed to determine if they are realistic to promote compliance and enforcement.
D. Promote Stakeholder Education and Participation
Efforts will be undertaken to raise the awareness of residents and commercial operators of the presence, conditions and governing regulations of the watershed. Education of the public about water quality issues will be undertaken to increase community support for the planning process and for allocating resources to implement actions.
Proposed public education activities include, but are not limited to:
· Distribution of the Allen’s Creek Watershed Plan to significant and interested Stakeholders.
· Formation of a city-wide Allen’s Creek Task Force to work with Stakeholders in the creekshed.
· Development of an Allen’s Creek WebSite that includes the current Watershed Management Plan, meeting notices, maps and other relevant information.
· Linking monitoring stations to an Allen’s Creek WebSite. For example, the City of Palo Alto, California, has established a “Creek Level Monitor” web site that is accessible from the city's home page[17] that updates flow information at key points along the city's three major creeks every 90 seconds.
· Submitting letters to the editor or “Other Voices” to the local newspaper.
· Contributing expertise on stormwater issues at public meetings and to various city committees, commissions and task forces, illustrating the interconnectedness of stormwater with most human activities.
· Conducting watershed walks along specific branches of the creek, discussing ravine, wetland and woodland protection, stormwater surging at manhole covers, localized flooding, etc.; these walks could be a part of organized environmental awareness events such as Huron River Day.
· Production of brochures describing the Allen’s Creek Watershed and key issues.
· Conducting informational and educational mailings, such as the tip cards produced by the City of Ann Arbor Water Utilities Department and the Huron River Watershed Council, that provide homeowners and businesses information on strategies to mitigate impacts on the water quality of Allen’s Creek.
· Making presentations and leading discussions at community events and gathering places, such as neighborhood schools and neighborhood organizations
· Publishing informational articles in neighborhood group publications, such as “The Old West Side News.”
· Development of programs to promote voluntary fertilizer reduction through changes in lawn care practices and by encouraging soil testing before applying fertilizer (this program is developed in greater detail in Appendix D on page 34).
E. Promote Innovative Programs
1. Stormwater Detention and Retention Facilities
The feasibility of stormwater detention and retention facilities should be evaluated for the Allen's Creek system. By reducing the rate of delivery of surface water runoff into the waterways, risks of flooding and delivery of pollutants will be reduced. Ideally, stormwater detention and retention facilities would be located in the headwaters of the main stem or three major branches (see Appendix E on page 36 for specific potential sites). Stormwater detention structures such as rain-barrels, cisterns, and rain gardens are the primary options for providing on-site stormwater management on small sites in a heavily developed watershed such as the Allen's Creek. Large-scale landscape projects or underground detention tanks are options for larger sites.
Landscape approaches. Aboveground landscape approaches offer multiple benefits, including aeration, filtration and absorption of water, potential replenishment of groundwater, and slowed rate of delivery of water to the main water courses. These attributes improve water quality while reducing risks of local flooding. Landscape approaches include development of wet meadows, wetlands, ponds and water gardens. Large-scale, aboveground landscaped stormwater detention facilities can be modeled after the Buhr Park project in the Malletts Creek Watershed. Buhr Park has been retrofitted with a wet meadow and will soon have additional stormwater landscaping integrated into its grounds. The University of Michigan recently performed a study on the use of rain gardens in the Mallet's Creek Watershed in Ann Arbor. This study concluded that up to 15% of stormwater in the Mallet's Creek watershed could be managed through implementation of ecological landscaping retrofits such as rain gardens and that up to 50% of the watershed residents were receptive to the idea. The City of Ann Arbor could contract a feasibility study on the costs and benefits of retrofitting the entire Allen’s Creek watershed with rain garden detention.
