SMART SEWERING:

Using Water Infrastructure to Promote Smart Growth, Water Sustainability and Development of Renewable Energy

Project Background

Town of Littleton. Click map for larger image.

In 2010, the Town of Littleton embarked on a Smart Sewering project that investigates the feasibility of using a combination of zoning changes and selective sewering to promote growth in the downtown area while also limiting sprawl in other parts of town.  Currently, the town has only septic systems and no sewered areas.  Littleton was selected for this project by CRWA because of our close ties with the town (CRWA’s director lives in the town), the fact that the town has no sewer (i.e. a blank slate) and septic problems that currently limit growth, plus the Town’s willingness to work with us on developing this new Smart Growth concept.

With help from the Metropolitan Area Planning Council (MAPC), the town has created a development district by approving two zoning amendments (May 3, 2010) at a Special Town Meeting.  The amendments established a Village Commons (VC) district and an adjacent Beaver Brook West Overlay (BBWO) district.  The VC area has been approved for mixed use zoning while the BBWO allows for mixed use development over the underlying industrial and business zones.  The development district is in the downtown area. For more information about the development districts visit the Town of Littleton's website.

The Board of Selectmen has appointed an eleven-member Sewer Feasibility Study Committee with a $50,000 budget and CRWA is donating $100,000 of services to the town (via the Barr Foundation) to assist in this project.  These funds will be used to define project goals, define the scope of work, and work closely with engineering and economic consultants.

Project Description

The project will create a new growth paradigm for small towns in New England by using water infrastructure to focus downtown development and preserve the character of the town.  CRWA will develop a planning document that assesses the technical feasibility of developing the downtown development areas by evaluating selective sewering and treatment of wastewater, energy generation at the wastewater plant, and future stormwater infrastructure requirements.  We have met with the Massachusetts Department of Environmental Protection (MassDEP) to discuss the project concept and they encouraged us to proceed.  We are looking for a consultant with expertise in spatial planning, wastewater engineering economics, environmental economics, and public finance to assess the economic feasibility and financing needs of this project.

Most wastewater projects in the state of Massachusetts and in the nation utilize large regional systems because the unit cost of treating wastewater is significantly lower than for small local systems.  This is a simple result of economies of scale.  However, systems with large capacity and geographic scope encourage uncontrolled widespread residential, allow commercial and industrial growth that alters the rural and historic character of a place, and damage local streamflow quantity and quality.

A small local wastewater system would do exactly the reverse.  It would focus growth in the sewered area, limit sprawl in other more rural areas, and would have a small impact on local streamflow quantity and quality.  In fact, if the wastewater is of sufficient quality and the discharge location is carefully selected, it could actually restore depleted aquifers and streams.  There might also be energy generation potential at the wastewater treatment plant if anaerobic digestion were used to treat the wastewater.  These benefits all fit within the concepts of Smart Growth hence the name Smart Sewering for this project.

Despite the compelling Smart Growth benefits of this approach, there are many unanswered questions.  How much more expensive is a small local wastewater treatment system then a large regional one?  Can the wastewater also be used for energy generation?  What are the sources of revenue generation in this project?  What would be the potential growth rate in the downtown area and how would that affect the potential revenue stream, wastewater flows, and stormwater impacts?  Can we use the discharge of treated wastewater to restore water deficits in local streams?  This project seeks to answer the technical and economic issues posed by these questions.For more about this project visit the Town of Littleton's website.

Recent Achievements and Current Work:

• The project team uses a Geographic Information System (GIS) to create maps that display important site characteristics including soil characteristics, land use, distance and elevation difference from downtown, and distance from streams and wetlands.  That GIS effort will affect a site's suitability for groundwater discharge of treated wastewater from the proposed sewer system.  The team will use these maps to screen possible sites and select the best ones for on-site evaluation by a certified soils specialist.

• Town-owned parcels provide the least expensive option for a wastewater disposal site. Therefore, the team has added a layer to the map indicating town ownership, giving higher ratings to town owned land.

• Using a strategy called buildout analysis, the project team will determine the potential development in the Village Common and the Overlay West-Beaver Brook..  The task will yield residential units, commercial/industrial footage, and parking areas. This analysis uses zoning rules Aquifer and Water Resources areas to determine the maximum intensity of use.  Areas prohibited from development like the well Zone I area and the riparian buffers are excluded from this analysis.  These buildout calculations will help determine the future quantities of wastewater that the sewer system will be expected to handle.

• CRWA developed a spreadsheet that calculates the amount of wastewater produced by commercial, industrial, and residential development.  This spreadsheet will allow the project team to determine the quantity of water that the proposed sewer system will be expected to treat under various buildout scenarios.

Support

CRWA's mapping capabilities are made possible through the generous support of ESRI, Inc. the makers of ArcMap software. CRWA regularly uses ArcMap for mapping, managing data, and conducting spatial analyses.


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Updated February 22, 2011