Home > Projects > Fisheries

FISHERIES


Low Flow and Habitat Assessment

Background

Water supplies to businesses, homes, and the Charles River are decreasing.  Development in the upper Charles River watershed is the fastest in Massachusetts, and the demand for drinking water is the highest ever.  Meanwhile, new pavement and buildings are cutting off rainwater from groundwater that normally maintains in-stream flows during summertime peak demands and droughts.    Residents, politicians, and municipal officials are acutely aware of the low flow problems: summer watering bans are regularly in effect, and the development of new water supplies is becoming increasingly difficult.  

Water supply is not the only feature of the Charles River that suffers with diminishing flows.  Fish and other aquatic organisms are seriously harmed when pollution concentrations increase, and food supply, oxygen, habitat and spawning areas become limited during low flows. 

Temperature increases under low flows can make the river uninhabitable to certain fish.  Fish tend to congregate near undeveloped, tree-lined riverbanks to find food and protective cover for breeding and predation relief.  As the river water sheet recedes during low-flow conditions, so does this prime fish habitat.  Fish requiring the full run of the river may become stranded in larger pools as connections between the pools disappear.  

Goals & Objectives

CRWA is conducting an investigation to determine the effects of low flow on aquatic habitat.  CRWA will develop the in-house technical capability to conduct habitat assessments.  We will also develop baseline data of habitat conditions in the upper watershed.  Finally, we will increase the public awareness of low flow issues and the effects on habitat.  This project is funded by the Massachusetts Environmental Trust.

Our work complements a project being conducted by the United States Geological Survey (USGS).  The USGS will investigate methods for determining the stream flow requirements for sustaining fish and wildlife habitat in Massachusetts' rivers.  We will provide assistance to the USGS project by collecting flow related data, performing habitat assessments, and monitoring water quality at USGS monitoring locations.  

Project Work

Our research includes the following tasks:

  • Monitoring three sites a minimum of four times over different flow regimes.  Water depths over reference points at riffle sites will be measured.  Riffles are the first stream area to be critically impacted over low flow conditions.  
  • Examining these sites for habitat characteristics such as vegetation, land use, sediment/substrate, available cover, channel alteration, bank stability and protection.  USGS will train CRWA staff to perform habitat assessments, following the procedures outlined by EPA.   
  • Promoting public education by writing a newsletter article describing the project and including the information on our website.

Outcomes

The fieldwork done through this project has provided CRWA with a better understanding of the implications of low flow on aquatic habitat.  The findings indicate that there is an immediate need to conserve water and to increase the recharge of groundwater from rain- and snow-fall.  Because of this need, CRWA developed SmartStorm – a rainwater collection system that captures rooftop runoff, storing the water for non-potable uses and recharging excess water into the ground. 

As a result of this study, CRWA has proposed changes to the Massachusetts Surface Water Quality Standards that include stronger habitat protection and altering flow provisions.  CRWA also submitted to the Water Management Act a proposal to promote habitat protection by requiring permits for large water withdrawals and future development projects.

Increasing public awareness was another important goal of this project which we successfully completed. Our assessments were performed with the help of volunteer college interns, future environmental stewards who learned about low flow issues and will communicate their knowledge to others. In addition, the lead article in our winter 2001 Streamer newsletter was about the project, entitled “Fisheries on the Charles go with the flow” .
 
Download the complete final report for this project (PDF)..

More fish and fisheries projects