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Instream Flow Program: Water for People and Wildlife
Instream Flow Program: Water for People and Wildlife
Instream Flow Program: Water for People and Wildlife
Transcript of video:
New Hampshire’s streams and rivers are home to fish, playgrounds for boaters and paddlers, and sources of water for residents, farmers and businesses. Unfortunately, when water is removed from the river for drinking, bathing, crops, or industry, it is no longer available for instream users. Flow in the river can become so low that fish may not have enough water to survive.
The Instream Flow Program balances the competing needs of those who use water taken from the river with those who use water in the river such as swimmers, fish and wildlife. The Instream Flow Program looks at each stream individually and determines how much water is withdrawn from the river and how much water needs to remain. It then seeks to balance these needs by answering two important questions related to river flows – how much is too little? And, what do we do about it? Answering these questions requires a great deal of scientific data and even more public participation.
The first question of “how much water is too little” is complicated by the nature of streams. Stream flow patterns are complex and variable. Just as the amount of water in a river is different from day to day, there are also large variations over longer time periods.
This flow variability is also what allows a stream to support a diversity of species that have adapted to these different flow conditions. The Program uses these natural patterns of high and low flows to define the stream flow protection criteria.
Stress from flow conditions is a common and normal condition for the fish and plants that live in streams.
So when does some stress become too much stress?
The program determines how long low-flow periods persist, and how frequently they occur. To gauge the low flow conditions that separate normal from excessive levels of stress, the program identifies flows that support fish and river entities and evaluates when those conditions are not being met. Low flows that are longer, lower, or more frequent than normal cause excessive stress. The protected instream flow represents the flow levels, durations and frequencies which prevent that undo stress.
After establishing a protected instream flow, the program develops water management plans that describe how water users can get the water they need while maintaining protected instream flows.
Water management plans are developed jointly between the water users, dam owners, and the Department of Environmental Services. Based on their particular water needs, water users and dam owners operate as usual most of the time. However, when flow has been too low for too long, the water management plans clearly articulate the circumstances when operational changes apply and how water users can get the water they need.
There are three components of water management plans –
Water Conservation,
Water Use
and Dam Management
Together, these plans are designed to maintain and restore the natural stream flow pattern and to support water users’ needs.
The water conservation plans reduce water losses by reducing waste and repairing leaks so that more water stays in the river or the ground.
Water use plans identify how water users will operate to get the water they need when stream flows are low. Management may include actions such as outdoor watering restrictions or development of alternate water sources. By reducing discretionary water use and using storage ponds or wells, water remains available for use while reducing or delaying the impact on the stream. For example, one municipal water system uses river water when it is plentiful, but when stream flows are low, they switch to their groundwater wells that have little or no impact on stream flow.
The final component for restoring the stream flow pattern is dam management, which is applied in extreme conditions when conservation and water use changes are not enough. Under a dam management plan, a two-day pulse of water is released from selected lakes to relieve the stress of abnormally long dry periods.
The pulse mimics the natural effect of historically common rainstorms. These pulses are carefully designed and used in a manner that also protects lake ecology and the recreational interests of lake users.
Because water truly is fundamental for all life, the public has a stake in how rivers are managed. The instream flow program recognizes this by providing frequent opportunities for public participation. The public can participate by helping to select the next river for instream flow protection, by providing input at public hearings and information meetings, and by becoming active on a Local River Management Advisory Committee. Similarly, the program also proactively seeks input from water users and dam owners in the watershed on their management plans and agency decisions.
The Instream Flow Program balances stream flow protection with society’s need for water. It answers the important stream flow questions of “how much is too little, and what to do about it.” The program applies river-specific science to define protected instream flows and water management plans so that there will be enough water for people and wildlife for many generations.