Storm water is rainfall and snowmelt that runs off streets, parking lots and driveways and into storm sewers where it drains to wetlands, streams and lakes. Storm water management is a local and national problem. The National Academy of Sciences has issued a special report (Urban Stormwater Management in the United States) on the damages of storm water and the challenges and opportunities of managing it. Among its conclusions are these:
“The rapid conversion of land to urban and suburban areas has profoundly altered how water flows during and following storm events, putting higher volumes of water and more pollutants into the nation’s rivers, lakes, and estuaries. These changes have degraded water quality and habitat in virtually every urban stream system. The Clean Water Act regulatory framework for addressing sewage and industrial wastes is not well suited to the more difficult problem of stormwater discharges.” National Academy of Sciences, 2008.
Locally, the Lake Wingra Watershed generates an estimated 82,968,732 cubic feet per year of storm water runoff, according to figures released in June, 2013 by Strand and Associates Engineering of Madison. According to estimates from Ken Bradbury of the Wisconsin Geologic and Natural History Survey (WGNHS) the average annual recharge to the groundwater is only 32,892,637 cubic feet. (Estimates contained in June 28, 2013 meeting minutes of the Lake Wingra Watershed plan Infiltration Team. Click here for the minutes.)
This means less rainfall is percolating down to the groundwater and more is just running down the storm drain. Over time, this imbalance alters hydrology and damages ecosystems throughout the Lake Wingra watershed. In addition, storm water facilitates the spread and establishment pest species by moving their seeds around and by provided disturbance niches for germination and growth of weeds.
Many groups are tackling the watershed’s storm water problems. The Friends of Lake Wingra has recently written a Stormwater Management Initiative that aims to tackle the problem from a watershed-wide perspective. The problem is so severe that the UW-Madison Arboretum has developed a special policy on storm water management policy that lays out management values, principles, and goals. (see below.) The topic was the subject of a poster session at a meeting of the Society for Ecological Restoration.
UW-Arboretum Storm Water Management Policy
Arboretum Committee Adopted – May 3, 2005
Since its designation in 1934, the 1,260 acre UW-Arboretum has coped with storm water runoff from the surrounding watershed. The impact of this runoff on Arboretum ecosystems are many, including: altered groundwater hydrology; erosion of the landscape; spread of invasive species; channelization, degradation and in-filling of wetlands and marshes; loss of natural terrain to storm water management infrastructure; and contaminated sediments and degraded water quality in Lake Wingra and Wingra Creek
To address these problems, and guide future storm water management in the Arboretum, the following storm water management policy for the University of Wisconsin Arboretum is adopted to provide guidance for the following activities:
1.Development of Arboretum policies and procedures as they pertain to storm water management.
2.Design, budgeting and implementation of storm water management infrastructure on Arboretum property.
3.Coordination and collaboration with surrounding municipalities and other watershed partners on issues related to storm water management.
4.The development of research and outreach education activities that utilize or are affected by storm water runoff.
5.Planning activities by similar facilities or other groups managing storm water runoff.
Part I. Arboretum Storm Water Management Values
Administered through the University of Wisconsin-Madison Graduate School, the Arboretum is a multi-disciplinary teaching and research facility with the mission: “We conserve and restore Arboretum lands, advance restoration ecology and foster the land ethic.” The Arboretum recognizes its role as one of many stewards of the water resources of the Lake Wingra and Lake Waubesa watersheds, and also that the management of UW-Arboretum lands takes place within a system of values that may differ from those applied to managing storm water in the surrounding urban areas.
To better guide the storm water planning process, and to provide criteria for making decisions about storm water management options in the future, the UW-Arboretum Committee has adopted (2004) the following management values, which represent ideals to be achieved:
Managing storm water on UW-Arboretum property should attempt to maintain (or restore) conditions of storm water transport and infiltration, that best serve Arboretum restoration objectives, while protecting the environment.
Flows of storm water runoff onto Arboretum property resulting from the surrounding urban areas should be controlled to pre-settlement levels to the extent possible, and managed for minimum impact upon Arboretum ecosystems.
1 Arboretum Committee adopted, October, 2004
The quality of storm water runoff (e.g. nutrients, solids, temperature) entering Arboretum ecosystems and draining to surface waters, should be consistent with pre-settlement quality.
Any construction of storm water management infrastructure (e.g. detention ponds and dikes) on Arboretum property should serve and enhance Arboretum restoration, teaching, research and outreach objectives
UW-Arboretum should encourage wise storm water management practices throughout the surrounding watershed community by example and through education.
These values influence the criteria used to evaluate a range of storm water management options, and they guide decisions made for implementation of storm water management practices.
Part II. Guiding Principles for Storm Water Management
The Arboretum, by virtue of its low topographic situation and urban watershed, has a larger burden of storm water runoff than an equivalent area in an un-urbanized watershed. While the Arboretum can only manage storm water within its boundaries, it can also advocate for improved storm water management by the municipalities, businesses and homeowners in the surrounding watershed. These guiding principles for storm water management will govern the implementation of storm water management practices on Arboretum property, and influence the adoption of practices elsewhere in the watershed.
1) Storm water is best managed where the rain falls, before runoff can accumulate. This requires both on-site and off-site management approaches.
2) Reducing flows of urban runoff onto Arboretum lands is key to restoring damaged ecosystems.
3) While our goal is to minimize the impact of storm water runoff on Arboretum ecosystems, changes in storm water management practices must not lead to further degradation of groundwater, downstream ecosystems or surface waters.
4) Infiltration of runoff will be implemented wherever feasible, to restore depleted groundwater levels and reduce discharge to receiving waters.
5) Runoff management and infrastructure on Arboretum lands will be configured to support research, restoration and outreach objectives.
6) In order to protect the Arboretum from catastrophic spills of chemicals from up-gradient commercial, industrial and transportation sources, the Arboretum will work with neighboring businesses and municipalities to put spill control/response plans in place to minimize the potential for spills entering the Arboretum.
7) Any modifications to storm water outfalls will incorporate methods of controlling or capturing spills of chemicals before they enter the Arboretum storm water management system.
8) Ponds and conveyances will be designed to minimize the impact of chloride-bearing winter runoff. Outflows of detention ponds, detention basins and other structures will be designed to disperse flows in order to prevent down-gradient scouring and erosion.
9) Storm water infrastructure will be designed to accommodate long-term maintenance and periodic rehabilitation.
10) Funding for design, construction, monitoring and maintenance of storm water management infrastructure, and for outreach education to improve watershed-wide management practices, should come from a mix of municipal, state, federal, private and University sources.
11) Runoff that is not conveyed by the storm water management infrastructure will be managed to minimize its impact upon Arboretum ecosystems.
12) The effectiveness of the Arboretum storm water management system will be measured using physical, chemical, and biological parameters that describe direct and indirect effects, to demonstrate progress toward achieving management goals, and to support research and education.
Part III. Goals and Anticipated Outcomes of Improved Storm Water Management
The Arboretum sets forth the following ten-year goals for improving runoff management in the surrounding watershed:
A 25% reduction in the volume of runoff entering the property, and;
A 40% reduction in total suspended solids (TSS), nutrients and other contaminants in storm water entering the property.
Achieving these goals will require the cooperation of the surrounding watershed, through increased infiltration of storm water and improved runoff management.
The values and guiding principles described in this policy are also expected to result in the following overall outcomes:
A. Improved Watershed-Wide Practices –
Knowledgeable municipal and business partners, and watershed residents, taking action to improve storm water management practices in the surrounding watershed.
Watershed-wide goals for reducing runoff flows and improving runoff water quality, and for the adoption by up-gradient neighbors of rain gardens, pervious surfaces and other beneficial management practices.
Advances in understanding of the performance of innovative storm water management techniques.
B. Beneficial Changes in the Arboretum –
Measurable improvement in the quality of surface and subsurface waters, resulting from storm water treatment and infiltration.
Increased longevity, and reduced maintenance, of storm water infrastructure located on Arboretum lands.
Reduced degradation of Arboretum ecosystems by storm water runoff and associated invasive species.