Instream Flow

The Lamprey River below the Packers Falls Bridge. Photo by Jerry and Marcy Monkman.

Background

The water that ultimately makes its way into the Lamprey comes from precipitation, directly via runoff, and indirectly from groundwater. On average, 20 inches per year of water comes from overland runoff. About half of this occurs during the months of March, April, and May. While in some watersheds low flows in summer and fall are augmented by adjacent aquifers, the Lamprey watershed contains relatively few aquifers in direct contact with the river.Instream flow, or the amount of water in the river at a given time, is important for several reasons:

Low water levels cause a rise in temperature with sometimes severe impacts on aquatic organisms; for example, warm water holds much less oxygen for them than cold water.
When flows are low, any contaminants become more concentrated, which can cause wastewater treatment plants to have difficulty meeting their permit requirements.
Very low flows cause wetlands to dry up and expose river banks, making aquatic animals more vulnerable to predation by raccoons and other predators.
The Lamprey River provides the largest volume of fresh water compared to other sources for and to the Great Bay Estuary. The volume and rhythm of flow to those ecosystems are critical to their health.
Finally, humans are affected because a low river means less recreation, poorer water quality for swimming, and shortages for municipal and commercial water supplies.

Many seacoast towns are facing a shortage of safe, reliable drinking water for their residential, commercial, industrial, and community needs. As the largest freshwater river in the Seacoast of New Hampshire, the Lamprey is viewed by many area towns as a possible source to augment their existing water supplies.

The joint University of New Hampshire/Durham Water System has been the largest consumptive user of the Lamprey (71 million gallons in 2004). UNH has used 70% of the system’s water, which on average produces 1 million gallons of water per day. The system has submitted a request to NHDES to increase the amount of water to be taken from the river.

Alternatives for a UNH/Durham water supply have been investigated, such as groundwater beneath the campus or the Spruce Hole aquifer, a potential major source of water for the system. However, as of 2006, plans to develop alternative water sources have not been initiated.

In addition, Newmarket is evaluating surface water withdrawals from the Lamprey River system to augment their two existing town wells and is also searching for new locations for groundwater wells. The town has instituted mandatory water bans for the past 2 years for people on town water. The Newmarket Conservation Commission has promoted water conservation by selling rain barrels and has facilitated the adoption of an ordinance that prohibits water withdrawals from surface waters along roads.

Because the Lamprey is a protected river under the NH Rivers Management and Protection Program, by statute its instream flows must be protected for the full range of human and ecological purposes. The regulations have yet to be developed, but the Lamprey is one of two rivers chosen for a pilot study of how much stream flow should be maintained, and how it should be allocated among competing uses. This involves a comprehensive study of the river’s resources, from archeological sites to fish, to establish the minimum flows. The second stage is to develop a management plan to determine how to maintain those flows, regardless of the rainfall in a given year.

The pilot Lamprey Instream Flow study includes new information about both ground and surface water in the corridor, including the effect of aquifers and groundwater on recharge of the river. The use of water in both the NH RMPP–designated towns of Lee and Durham and the towns upstream of them are to be examined in the Instream Flow study. However, the study does not include towns downstream of the designated river segment, so Newmarket is excluded from the study.

Groundwater plays an integral part in planning for protection of river flows. Not only does groundwater augment surface water stream flow, but it also provides an alternative water source for human use. Knowing where and how much groundwater is available for watershed communities’ use is thus intimately tied to protecting the Lamprey’s flow levels. So, also, is planning for wells withdrawing water near the river, including both large withdrawals and large numbers of private wells. A U.S. Geological Survey (USGS) groundwater/aquifer study has provided new information about the location of groundwater sources in NH Seacoast towns, including the Lamprey watershed, causing some municipalities to do further work in pinpointing the location of their groundwater resources.

Accomplishments:

Worked to influence water withdrawal policies by the UNH/ Durham Water System, including fact-finding and campus education to promote water conservation.
Investigated how efficiently the UNH/Durham Water System is using its water resources and any potential causes of wasted water, such as leaks in the system.
Participated in the state’s Instream Flow study by gathering data, identifying important river resources to protect, and reviewing draft documents. LRAC members serve on the Technical Review Committee and the Watershed Management Planning Advisory Committee for the study.
Worked with NHDES to establish minimum flows related to withdrawals from the Lamprey by the UNH/Durham Water System. These minimum flow and flow recording requirements became part of the UNH/Durham 401 Water Quality Permit.
Assisted in documenting impacts on the river when the Wiswall impoundment was drained for engineering work on the dam in 2006.

Goal

Maintain a viable quantity of water in the river during all seasons sufficient to support and sustain the river’s ecological and recreational resources, while considering the need for agricultural and municipal use.

Key Future Actions:

Encourage strategies that minimize impervious surfaces in the watershed and allow stormwater runoff to percolate into the soil, recharging groundwater that maintains river flows.
- Encourage use of impervious surface information contained in the stream buffer study done by UNH and the New Hampshire Estuaries Project (NHEP).
Keep water in the Lamprey watershed.
- Encourage communities with municipal wastewater treatment to return their treated wastewater to the same watershed, whether via surface waters or through land application.
- Participate in the discussion on the legislative Regional Wastewater Study to assure that options will protect river flows in the Lamprey River watershed.
Help ensure NHDES water conservation rules are applied to all new Lamprey withdrawal requests.
Promote a NHDES permitting process for currently unregulated users of water from the river.
- Investigate the potential for lowering the minimum daily quantity of water use that must be reported to NHDES (currently 20,000 gallons per day).

• Support municipal officials in developing long-range water plans.

- Encourage the review of existing information about aquifers, including location of water, location of drinking water sources, build-out analyses that include water budgets, and evaluation of existing and new ordinances.
- Promote watershed-wide water planning including limits on impervious surfaces and water budgets with projected supplies and future needs.
- Host an annual water forum for Newmarket, Durham, Lee, and Epping.
Work with Durham to promote efficient water use, and thereby reduce need to withdraw water from the Lamprey River.
Work with the Town of Durham, NHDES, and USGS to develop and implement a plan to measure or estimate outflow from the Wiswall Dam and inflow to the impoundment, as called for in the 401 Water Quality permit for the UNH/Durham Lamprey River withdrawal.
Work with the National Park Service to implement its authority under the Wild and Scenic Rivers Act to review and condition federal permits or projects potentially affecting stream flow or the free-flowing character of the Lamprey River.
Actively promote water conservation.
- Encourage communities to consider mandatory conservation measures to augment volunteer efforts during droughts.
- Develop homeowner incentives to conserve water.
- Promote the use of gray water systems and drip irrigation systems.
- Offer information to the public to help users know what their water conservation options are.
- Encourage the UNH/Durham Water System to reduce unaccounted-for water to less than 15%.
- Consider partnering with UNH water conservation efforts.
Raise awareness about water issues among community residents.
- Use the internet, LRAC website, public workshops, print media, an advertising campaign, and events such as road races, river rafting, geocaching, and canoeing to focus public attention on wise use of water.
- Consider hosting an annual river event with water quality and river flow protection as a theme.