The Massachusetts Sustainable Water Management Initiative demonstrates the use of (1) a duration-curve regression approach to build a hydrologic foundation, (2) bioperiods as a temporal basis for setting flow criteria, (3) quantitative flow-ecology response curves to inform decision-making, and (4) a management framework that associates implementation actions with different condition goals.
Responding to water quality and quantity concerns, the 1987 Massachusetts Water Management Act (WMA) established a water withdrawal permitting system. Twenty years later, implementation of the Act was falling short of its objectives, as evidenced by persistent impacts from stream depletion. Consequently, environmental groups appealed permit decisions for not adequately protecting rivers and streams from excessive water withdrawals, and filed legislation requiring the development of environmental flow protection standards. In 2009, responding to continuing controversy, the state launched the Massachusetts Sustainable Water Management Initiative (SWMI). Both the social and scientific processes of SWMI closely follow the ELOHA framework.
An Advisory Committee representing water suppliers, conservationists, agriculture, state agencies, and other stakeholders was established to develop a comprehensive approach to water management, including water withdrawals. A Technical Committee representing the same stakeholders and state and Federal agencies was formed to help inform and scientifically ground this effort.
The hydrologic foundation is the Massachusetts Sustainable-Yield Estimator (SYE), a statewide, interactive decision-support tool developed by the U.S. Geological Survey (USGS) (Archfield et al. 2010; Weiskel et al. 2010). Quantile regression is used to estimate the flow-duration curve for the ungaged site, based on climate and physical parameters. A minimally altered reference gage is then selected as described by Archfield et al. (2010) and used to transform the flow-duration curve into a daily time series of baseline flows.
Current-condition flows are calculated by adding and subtracting water withdrawal and return flows. Monthly water use data are divided evenly by the number of days in the month. STRMDEPL (Barlow 2000) may be used to distribute stream depletion due to groundwater pumping over time, given well locations and basic aquifer characteristics.
The Technical Committee of stakeholders, guided by state resource agencies, identified four seasonal bioperiods necessary to support biological needs of resident fish communities and fluvial-dependent diadromous species. For each sub-basin, a range of flow statistics was calculated, including median flow during January, April, August, and October. Flow alteration was calculated by comparing baseline to current-condition data.
Flow-ecology relations based on data from 669 fish-sampling sites are described in two USGS Scientific Investigation Reports by Armstrong et al. (2010. 2011). Literature review guided the selection of a set of flow-sensitive fish metrics, including species richness, abundance of individual indicator species, and abundance of species grouped based on life history. A set of environmental variables was calculated for the contributed watershed area for fish-sampling sites, including land cover, land use, fragmentation, and flow alteration variables.
The generalized linear modeling (GLM) approach led to a small set of models for describing the relations between fish-response and environmental/anthropogenic variables. August median flow was found to be a primary predictor of biological integrity for fish and wildlife communities.
The Massachusetts Department of Fish and Game (DFG) led a process of categorizing the current condition of the state’s flowing waters using fish community metrics as a surrogate for ecological integrity. All sub-basins in the state can be placed into one of five Biological Categories based on known natural watershed characteristics along with estimates of impervious surface and percent alteration of the August median flow.
The collaboration among state agencies and a wide range of stakeholders culminated in November 2014 when the Water Management Act was revised to incorporate the new and modified permit requirements, that are intended to improve the sustainable management of water for the well-being of the Commonwealth’s citizens and for protection of the environment. The Sustainable Water Management Initiative is intended to protect and improve existing ecological conditions in streams even as future withdrawals are expected to increase.
Standard water withdrawal permit conditions under the revised Water Management Act include efficient water use, with an average residential demand of under 65 gallons per person per day, unaccounted-for water of less than 10%, and limits on non-essential outdoor water use. Impacts of increasing withdrawals on streamflow must be mitigated, and groundwater supply systems must be operated to minimize impacts in areas of groundwater depletion. The
regulations are available from the Massachusetts Department of Environmental Protection.
