Sustainable Water Supply Management

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Today's complex water supply issues demand an integrated watershed-based approach

Compwatershedeting Water Needs
Reflecting on this long snowy winter, it’s hard to understand why New England needs to implement sustainable water management initiatives to protect our precious water resources. In New England, we receive on average about 42-50 inches of precipitation a year. About 25% of this amount percolates into the ground and is stored as groundwater. How do we balance water use among competing uses? How do we provide enough water for public needs while still protecting our rivers and lakes?

In New England, water extraction for public and private use has historically followed the old English Common Law precept of “Absolute Dominion.”  In the case of groundwater, absolute dominion dictates that landowners own the water below their land, or own rights to the river, lake or stream abutting their property.

This concept of water ownership continues to evolve through changing regulation at the state level as we expand our understanding of aquatic and riverine habitats. Regulation seeks to balance consumptive and extractive water use with competing needs for stream flows to assimilate wastewater effluent flows, maintain adequate aquatic habitat for fish, insects and invertebrates, and to maintain wetland ecosystems. Maintaining water balance is the primary focus of new regulations so that stream flows do not suffer depletion from cumulative extraction of water within watersheds.

 

Evolving Regulations
The Commonwealth of Massachusetts has been at the forefront of balancing water use through initial enactment of the Water Management Act (WMA) in 1986.  In 2014, a new family of regulations referred to as the Sustainable Water Management Initiative (SWMI) was incorporated into the WMA, enhancing requirements to demonstrate balanced water use in each watershed or basin in Massachusetts.
The revised WMA regulations incorporate a new approach to determine basin safe yield and the concept of stream flow criteria. The updated WMA withdrawal permit process will now categorize all permit applicants through a three-tiered process with specific restrictions and additional review specified for each tier.  Tiers are established by each applicant’s baseline, withdrawal request, Biological Category, and Groundwater Withdrawal Category.

Balancing Competing Demands
Along with the standard conditions that apply for all permitted groundwater and surface water withdrawals, SWMI introduces three new criteria to the WMA permitting process:

  • Minimization
  • Mitigation                     
  • Coldwater Fisheries Resource

Minimization
Minimization correlates to the groundwater extraction at source locations. MassDEP has set a limit of 25% Net Groundwater Depletion (NGD) during the month of August. Exceeding this limit requires permittees to identify and implement ways to reduce withdrawals or return groundwater to basins or sub-basins to improve stream flow. See sidebar for the minimization guidelines.

Mitigation
For public water systems, water withdrawals requested above a permit’s baseline will require mitigation in order to receive approval for the increased withdrawal by receiving “credits” to compensate for the impact.  A credit is calculated by subtracting the savings through enhanced demand management and wastewater adjustments from the increase over baseline. SWMI provides six categories of options for mitigation. See sidebar for list of categories.
Each option is classified as either “direct mitigation” (quantitative credit system) or “indirect mitigation” (qualitative credit system). Direct mitigation will directly result in enhanced stream flow, stream flow contributions, or surface water releases. Indirect mitigation are environmental improvements that will help compensate for stream flow impacts resulting from withdrawals. Some examples of a direct mitigation are optimized surface water releases, stormwater discharge, or infiltration and inflow removal. Indirect mitigation is not amenable to volumetric calculation. Some examples are installing and maintaining a fish ladder, removal of a dam or flow barrier, or replacing a culvert.

Coldwater Fisheries Resource (CFR)
CFRs are waters identified with cold water fish species as determined by the Massachusetts Division of Fish and Wildlife (DFW). Coldwater fish are interdependent with groundwater, and withdrawals greatly impact the CFR. Any applicant that is withdrawing water from a sub-basin that contains a coldwater fishery (CFR) will need to meet additional requirements as well as consultation with MassDEP and the Executive Office of Energy and Environmental Affairs (EEA) regarding the minimization of impacts to their CFR.

Integrated Watershed Approach is Required
Water suppliers will now be required to integrate and understand stormwater, wastewater and water supply and how these needs compete and balance within watersheds. SWMI helps provide a balance of water use among competing users, and helps protect our precious water resources through implementation of a statewide set of rules that seek to enhance water balance in watersheds to meet society’s needs. A Massachusetts grant program has been established to help public water systems with funding for mitigation and minimization efforts. About $1.8 million dollars was distributed in 2014 to support this initiative.

Wright-Pierce specializes in helping communities manage their water resources in a holistic, integrated watershed-based approach.

If you have comments or questions, I welcome hearing from you.
                    

JPM_Jeff-Musich  Jeff Musich, PE
  Senior Vice President
  Water Practice Group Leader

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