Plymouth, Massachusetts: Suburban Case Study
The Pinehills, Plymouth, MA
The Pinehills development will comprise nearly three thousand homes; 1.3 million square feet of commercial space in the Village Green or town center; four golf courses; and significant areas of protected open space when completed in 2014. The project was planned as an open-space mixed used development (OSMUD), a special floating zone passed by Plymouth town meeting, as an alternative to the standard subdivisions which predominate the region. Pinehills serves as an excellent example of compact design, reduction of impervious surfaces, water conservation, wastewater re-use, and historic preservation.
- Overall density of the project is approximately one residential unit per acre
- Many of the villages are developed at densities of eight units/acre or greater
- Minimum lot size is 6,000 square feet
- Homes represent a broad mix of housing types, both single-family and multi-family
- Homes range in price from just under $400,000 to more than $2 million.
- The homes were sited not on a plan in the office but on the ground based on the views they would offer and also privacy. Lot lines were drawn once the homes were plotted.
- The 3,000-acre site has unusual topography and only 952 acres of buildable land
- 70% or 2,125 acres of land will be retained as open space including both active (golf) and passive (wildlife, water resources protection, and hiking areas) uses.
- The design results in shorter roads to access the residential sites.
- All roads and sewer and water facilities are privately owned.
Water Supply and Conservation:
Early in the project design process an ideal public water supply site was identified by water supply hydrogeologists and engineers.
Water withdrawals to be used for golf course irrigation in the Eel River watershed were compensated for using an innovative stormwater management program.
The Pinehills comprehensive sewer system delivers wastewater to a state-of-the-art treatment facility which has been carefully sited hydrologically downgradient of the water supply site.
Lincoln, Massachusetts: Rural Case Study
Drumlin Farm Wildlife Sanctuary
The Drumlin Farm Wildlife Sanctuary is a 232-acre facility that features a nature center, walking trails, farmyard and seasonal farm stand selling sustainably grown foods. A new educational facility called the "Discovery Barn" is planned near a pond and a vegetated wetland and will incorporate a range of LID strategies to mitigate impacts. Selected LID techniques or Best Management Practices (BMPs) included bioretention systems, cisterns, a green roof, and a vegetated filter strip.
A bioretention system, also referred to as a "rain garden" or a "biofilter," will intercept road runoff and filter it prior to discharge to a nearby pond.
Water quality swales are shallow, open ditches that can improve water quality by infiltrating and filtering the water through vegetation that grows within the swale. They can be used to retain and pre-treat stormwater runoff. At Drumlin Farm, a water quality inlet and swale will treat runoff from the horse paddock.
Cisterns and Recycled Roof Runoff:
Runoff from the roof of the new building will be collected in cisterns and utilized at an adjacent greenhouse as irrigation water.
This will serve to reduce runoff and also is intended as a demonstration project for educational purposes.
Vegetated Filter Strip:
A vegetative filter strip is proposed next to an existing chicken "coop" building, which is close to a nearby pond. The strip will capture any stormwater runoff from the chicken "coop" and will provide filtering of the runoff prior to infiltration to the groundwater.
Acton, Massachusetts: Suburban Case Study
The Discovery Museums
The Acton Discovery Museums installed an outdoor LID demonstration site at the Science Museum building to showcase LID technologies while increasing the amount of groundwater in the watershed through stormwater recharge.
A Stormwater Recharge Project:
The Discovery Science Museum's LID demonstration site incorporates many LID technologies including rain barrels, rain gardens, pervious paving, and gravelpave and grasspave systems. These technologies increase groundwater recharge by reducing stormwater run-off and pollution by removing particulates and contaminants from rainwater. Also slower infiltration through the soil provides cleaner high-quality water to the underlying aquifers and groundwater reservoirs of the Assabet River watershed.
Low Impact Development Technologies In Detail:
- Rain barrels capture rainwater from the roof and store it to use for watering adjacent gardens, planters, and the Grasspave system. These rain barrels are particularly useful during periods of low rainfall and summer water bans.
- The Rain Garden is an attractive natural area that captures rainfall and runoff from surrounding areas and holds water while allowing it to seep slowly into the ground. The rain garden is further sustained by water from the rain barrels.
- Grasspave is a plastic subsurface reinforcement structure that provides load-bearing strength while protecting grass root systems planted within it from compaction. Grasspave's high compressive strength also makes it ideal for heavy use areas such as parking lots and along public areas.
- Gravelpave is a porous paving system that uses a load bearing structure with open cups that contain and keep gravel in place. Gravelpave creates a porous surface so rainfall can filter into the ground and recharge groundwater.
- Pervious stone paving is a permeable concrete paver that has funnel-shaped openings that are filled with coarse gravel.
LID Project Partnership:
The Discovery Museums' LID demonstration project was generously funded by a $56,570 grant for design and construction from Intel, a local company based in Hudson. The $1.5 million Intel Fund provides direct support to projects which will recharge stormwater in the Assabet River watershed in order to increase the base flow of the river. Additional project partners were the Acton Citizens for Environmental Safety (ACES) and the Organization for the Assabet River (OAR). Design and construction were completed by GeoSyntec Consultants, Inc. of Acton.
Olmstead Green, Boston, Massachusetts: Urban Case Study
Olmsted Green, Boston, MA
Olmsted Green, to be built on a portion of the former Boston State Hospital site, will construct housing units and occupy more land area than any project in the City of Boston over the past 20 years.
The project is a 42-acre planned mixed-income mixed-use new construction project consisting of 287 market rate townhomes and condominiums, 153 affordable apartments, and 83 units of rental housing for seniors. This four year phased project will also include expanded programs and services including:
- childcare, youth, and senior programs
- a mental health rehabilitation facility
- a four season athletic and recreation facility
- a job training and education center
- an urban farm
A Sustainable Development Project:
Olmsted Green's design is based on the principles of sustainability, conservation of resources, low impact development, and accessibly priced energy-efficient "green" homes in a community setting dedicated to inclusiveness and healthy lifestyles. The campuses will feature year-round agriculture and aquaculture production, a small farm stand, and product market area.
Low Impact Development Design:
Olmsted Green is taking a Low Impact Development approach that will significantly improve the existing physical site conditions, increase the infiltration of rainfall into soils and groundwater, reduce surface flooding, protect and enhance wetlands on the property, and preserve existing mature specimen trees. LID methods will include:
- tree preservation
- soil amendents to improve vegetative growth and erosion control
- vegetated swales
- rain gardens
- subsurface infiltration
- permeable pavers and pavements
- Stormwater System Operations and Management Plan to keep these improvements effective over time.
Rain gardens and swales will be designed to capture runoff from frequent smaller storm events of 1-inch or less that occur year round. The rain gardens will both treat runoff and promote infiltration of rainfall. They will be designed to be incorporated into the landscape as natural features, will improve water quality of groundwater, and will maximize recharge in localized areas of the site. Overflows from the rain gardens will be directed to infiltration / detention systems designed for storage and peak flow reduction.
Stormwater Treatment and Infiltration Systems:
- Olmsted Green will have an extensive integrated underground stormwater infrastructure that will capture and slowly release of water from more than 1-inch rain events
- Underground "StormTech™" chambers will be used to avoid the need for any big ugly retention basins.
- Permeable patio tiles and asphalt pavement will be placed in the areas of housing on the site.
Stormwater System Operation and Maintenance Plan:
The success of the Olmsted Green's LID approach depends on proper construction, operation, and maintenance of all critical components. A detailed, readable, and user friendly Stormwater System Operation and Maintenance Plan document will stay on site and be an important resource for building and maintenance contractors.