Stormwater Pond & Greenway Tour

Grassman Ponds

This site is an example of a novel urban ecosystem. It is comprised of a patchwork of reed canary grass monoculture, upland remnant prairie, diverse shoreline plantings and second-growth woodlands.

A large area is dominated by reed canary grass surrounding a shallow pond. Despite the low plant diversity, the pond supports a great diversity of amphibian and invertebrate life; particularly dragonflies.

To the east, two newer, smaller ponds are primarily vegetated with native wet-loving species such as ironweed, glade mallow and cup plant. A dry slope running north of the larger pond may be a remnant prairie.

South Mendota Pheasant Branch Greenway - Blackwolf Drive Section

This pond and greenway system was severely impacted by 2018 floods. The northernmost portion of the greenway that runs along Attic Angel Circle was washed out and needed to be regraded and reseeded with a native prairie mix. 

The area is generally a fairly diverse prairie/wetland complex that receives a fair amount of targeted weed control. 

Goals include continuing to control crown vetch, non-native thistles, reed canary grass and pampas grass that invaded from residential ornamental plantings.

East Mendota - Pheasant Branch Greenway - South Tree Lane Section

This greenway was entirely reconstructed in 2020. This section of greenway is upstream from the undesigned East Mendota - Pheasant Branch North Tree Lane Section Greenway that runs from Haen Family Park up to the High Point and Old Sauk Road intersection.

Unlike the downstream North Tree Lane section of this greenway which was never clear cut, the heavily wooded greenway had primarily invasive, opportunistic tree species typical of areas once cleared for agriculture. The greenway reconstruct removed buckthorn, box elder, honeysuckle and other opportunities tree and shrub species that were casting dense shade, preventing the growth of a groundlayer and leading to erosion.

The site has been managed by an ecological restoration firm since reconstruction through 2024.

The area will be managed by an ecological restoration firm through 2022.  The herbaceous groundlayer is growing as hoped.

Silicon Prairie Ponds

These ponds are a typical example of the “twin” pond system combining a retention pond with an infiltration pond. Retention ponds, also known as wet ponds, hold water nearly all the time. Infiltration ponds, are designed to infiltrate water within a few days after a rain event.

Unfortunately the pond design here failed and both ponds hold water at all times. The vegetation in the area is almost entirely a reed canary grass monoculture.

Upper Badger Mill Creek - Regional South Basin

Perhaps the best example of a restored prairie-wetland pond in Madison, this five acre pond is dominated by a diverse array of native plants. The large size of the pond and the isolated location help protect the upland prairie planting from infestations. However, as the endpoint for a major greenway system, the pond is prone to wetland infestations from seeds travelling downstream.

Controlling purple loosestrife and willow sandbar along the shoreline are two major goals for the pond. The pond is burned on a 4-5 year rotating cycle to control woody invasives and help promote native plant growth.

East Mendota - Pheasant Branch Greenway - North Tree Lane Section

Unusually large and heavily wooded, this undesigned greenway supports one of the densest stands of mature oak trees on within our drainage system. Much of the understory is dominated by buckthorn, but stands of herbaceous woodland vegetation including spring ephemerals are scattered throughout. 

The unstabilized slopes surrounded by dense woods shade out the forest floor, leaving bare soil exposed and prone to erosion. This erosion contributes to falling trees which block the channel. Due to high levels of erosion, the City would like to stabilize the channel and create maintenance access. A plan for the entire greenway corridor will be developed with the community in 2023 and 2024 prior to beginning phases of detailed design and construction.

Mendota Spring Harbor Greenway - South Hill Drive Section

A classic example of a novel urban ecosystem, this wooded greenway has an interesting mix of legacy oaks, remnant woodland vegetation, buckthorn-choked second-growth, and native shrub clones. 

Resident volunteers made a great effort to clear out the invasive undergrowth starting in 2020.  The transformation should provide many benefits to the greenway including less sheet erosion from bare topsoil as herbaceous vegetation fills in; fewer downed limbs in the channel, and increased habitat and aesthetic value as native plant restoration efforts continue to be pursued.

Warner Park Greenway - North Sherman Section

An example of restored prairie in a highly urban area, this stormwater channel runs into Castle Creek and eventually, the Warner Park Lagoon. 

The goals for this greenway are to continue to maintain high levels of native prairie plant diversity, keep woody invasives at bay, and take up as much water, sediment and pollutants as possible to prevent them from reaching the lagoon.

Whitetail Ridge Detention Pond

An example of a detention pond that may dry out entirely in between rain events, this pond is a typical example of a low-diversity urban pond. The majority of the pond is dominated by a monoculture of invasive reed canary grass, with some upland burdock, teasel and musk thistles. Though mostly devoid of diversity, a surprising stand of native whorled milkweed (Asclepias verticillata) provides habitat to monarch butterflies and other native insects. When dry, the area may serve as additional recreational space for area residents. 

Goals for this site include controlling the broad-leaf invasives and preserving the whorled milkweed clone.

East Starkweather - East Towne Greenway

In 2023, a major reconstruction project began as part of this pond to provide additional flood storage and improve trash and sediment collection and removal.

This site faces some of the most challenging urban conditions including large amounts of pollutants and large influxes of stormwater from the nearby East Towne Mall area, heavy trash accumulation, and intense pressure from invasive species including a relatively uncommon invader, Javanica oenothera, a wetland invasive with only two other known infestations in the state.

This project was designed specifically around a stand of existing sedge meadow, a relatively uncommon find in unmanaged ecosystems in Madison.

The newly reconstructed ponds will be planted with a native seed mix heavily favoring sedge meadow species and managed by an ecologist until 2025.

Saturn Drive Ponds

These two ponds are examples of new developer-constructed ponds where native prairie and wetland vegetation became well established. While the ponds still have many invasives to contend with, particularly around the north pond where development of nearby housing units is still causing disturbance and acting as a weed source, the majority of site coverage is in native prairie and wetland plants.

Goals for the ponds include aggressively targeting invasive plants before they become well established, encouraging native plant growth by performing prescribed burns, and inter-seeding with native seed as necessary.

North Door Creek Greenway - Sprecher Road Section

A relatively diverse prairie channel running through a residential area. 

Goals include controlling invasive willows, teasel, cattails and biennial thistles while increasing native plant diversity.  As a highly visible median greenway, this site presents good educational and aesthetic opportunities.

Harrington Drive Pond

Part of the Door Creek wetland system, this pond has both a reed canary grass monoculture and a diverse assortment of prairie species. Some rarer species like the hemiparasitic wood betony (Pedicularis canadensis) help shape unique ecosystems on the site.

Goals for this site include preserving and expanding the native plant diversity into adjacent park land.

North Pennito Creek Greenway

Primarily grass and earthen, this greenway is showing undercut banks, channelization and ponding of water. 

Much of the length is mowed to turf by area residents.  Some of the area immediately in the channel has invasive reed canary grass growth. Neither turf grass, nor reed canary grass have particularly deep root systems effective at slowing erosion. 

This greenway will likely need to be reconstructed within the next decade.