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