Excerpt from: ABOVE THE FALLS -- A Master Plan for the Upper River in Minneapolis
http://www.ci.minneapolis.mn.us/citywork/planning/planpubs/above-falls/report/environmental-restoration.pdf
-------------- Water Filtration Parks: Retention and filtration of stormwater run-off is a crucial component of an ecosystem approach to improving the Upper River. However, sites devoted to improving water quality should be designed and constructed, not as simple exercises in engineering, but as additional amenities complementing the river and adjacent redevelopment. The concept of water filtration areas as parks has reached an exciting level of development, with stormwater ponds utilized as water bodies within open space settings designed for human interest and education. The Master Plan combines no-build zones reserved as view corridors to the river and downtown with Water Filtration Parks. These filtration parks are connected to the overall parks system, and in most cases should be designed to blend together seamlessly. However, most of the land utilized for ponding would not be owned by the Minneapolis Park and Recreation Board, but rather should be outlots within private development sites set aside for ponding. An option for future consideration might be the establishment of a public-private partnership to develop ponds and allow public access.
------- Features: Water quality ponds have such great potential as park features precisely because they store water, which has been a traditional part of park and pleasure garden design since their origins. The ecological, regulatory, and aesthetic converge, with a sharing of costs for pond construction between what is required to meet standards and the addition of certain public amenities to produce us eable parks. In addition to retention ponds, other basic features should include: -- Wetland plantings for increased ecological and aesthetic effect, -- Observation platforms, -- Trails, -- Educational signage.
------- A Model: As concern about water quality grows, municipalities around the globe have recognized the opportunity to combine stormwater ponds with parks. Many examples could be listed, but one new park is so outstanding that it provides the best model for a high-quality water filtration park. This park is the "Living Water Garden" in Chengdu, China, winner of the 1998 Top Honor Award from The Waterfront Center. The Living Water Garden transformed a polluted riverfront site in a highly urbanized area into an amenity that both cleans river water and educates visitors about the processes used. The park combines the finest in design - it is shaped to resemble a fish - with excellent engineering, utilizing an advanced constructed wetlands system to treat the water. Flowing through a series of ponds, or tanks, the water is purified by settling, anaerobic microorganisms, aeration, and a variety of wetland plants.
------- "Living Machine" Wetland Garden: An advanced constructed wetlands system is applied to the River City site in the Upper River Master Plan. Labeled the "Living Machine," after wastewater systems developed by John and Nancy Todd, the system utilizes inert filters and biological processes of living plants and microscopic animals to cleanse stormwater. The urban design of the water filtration park complements the surrounding high-intensity uses, collecting run-off from the area's impervious surfaces. The concept is the same as the wetlands park in China: a system of settling tanks and filters are combined with concrete-lined wetland "ponds." On this site, impervious tanks or "ponds" are recommended given the possibility of remaining soil contamination - water might only pick up more pollutants if allowed to filter through to the level of groundwater. The primary filters and settlement tanks remove grit and solids in the water, while anaerobic microorganisms in the tanks break down organic pollutants. The water would flow from one tank over a series of cascades, the splash and aeration increasing dissolved oxygen levels. The secondary filtration is provided by a series of ponding tanks with wetland species, and associated microorganisms, taking nutrients out of the water as they grow. The China system harvests wetland plants grown in the nutrient rich water for use as fertilizers and feed. The "Living Machine" would also require periodic maintenance. During winter the flow would slow or stop, as does the flow of surface run-off. In addition to water quality benefits, the "Living Machine" would provide an educational resource informing citizens about efforts and techniques utilized to clean stormwater. Signage would describe the various filters and plant species, and the improvements that each stage makes to the water quality. Finally, the last phase of treatment includes a fish pond , which could have ornamental fish or river species, leading to a large pool and fountain above the Skyline Amphitheater, providing a final burst of aeration to increase oxygen content before the water is allowed to flow to the river.
------ Other Water Filtration Parks: Of course not every water filtration park should be as elaborate as the proposed "Living Machine". Most parks would consist of simple one- or two-cell ponds, with wetland plantings, in a naturalized setting. Some might include aeration fountains or other devices to improve water quality. New techniques are sure to be developed over the implementation period of the Upper River Master Plan, yet the goals of improving water quality, creating wetland habitat, and education will remain constant.
. . . . . . . . . .http://www.ci.minneapolis.mn.us/citywork/planning/planpubs/above-falls
. . . . . . . . . . . . . . . . . http://www.mninter.net/~stack/living 002may2