View source for Draw-down

	<p align="left"><font face="Arial, Helvetica, sans-serif">'''Division of Fisheries and Wildlife'''</font></p>
        <p align="left"><font face="Arial, Helvetica, sans-serif">'''Drawdown Performance Standards for the Protection 
              of Fish and Wildlife Resources'''</font></p>
            <p align="left"><font face="Arial, Helvetica, sans-serif">Approved by the Fisheries and Wildlife Board on September 
              23, 2002</font></p>
            <p align="left"><font face="Arial, Helvetica, sans-serif">The Wetlands Protection Act requires that the Division 
              of Fisheries and Wildlife be notified of any proposed drawdown where 
              rare species habitat is involved. To identify areas of rare species 
              habitat, consult the most recent edition of the "Massachusetts Natural 
              Heritage Atlas" which contains maps of Estimated Habitats and Priority 
              Habitats of rare wildlife.</font></p>
            <p align="left"><font face="Arial, Helvetica, sans-serif">Drawdowns are commonly used as a technique to control 
              aquatic vegetation in many Massachusetts waterbodies. The Division 
              has statutory authority for regulating the take of these resources 
              under Massachusetts General Law Chapter 131 and Chapter 321 of the 
              Code of Massachusetts Regulations. Based on the Division of Fisheries 
              and Wildlife's knowledge and understanding of aquatic ecosystems, 
              the following performance standards were developed to protect fish 
              and wildlife resources when a lake drawdown is proposed.</font></p>
            <p align="left"><font face="Arial, Helvetica, sans-serif">For drawdowns exceeding 3 feet the Division of Fisheries 
              and Wildlife must be contacted directly for a site-specific review 
              of potential impacts to fish and wildlife resources. For drawdowns 
              of 3 feet or less, the proponent must either 1) contact the Division 
              of Fisheries and Wildlife for a site-specific review; or 2) meet 
              the performance standards below:</font></p>
            <p align="left"><font face="Arial, Helvetica, sans-serif"><i>1. Drawdowns must commence after November 1st.</i></font></p>
            <p align="left"><font face="Arial, Helvetica, sans-serif">Drawdowns have been documented to be effective for 
              vegetation control in certain situations but still constitute an 
              artificial disturbance. Consequently, any drawdown should take place 
              for the minimum amount of time required to accomplish the lake-management 
              goal for which the drawdown is conducted. A November 1st start date 
              for the drawdown will allow the following conditions to be met: 
            </font>
            <div align="left">
              <ul>
                <li><font face="Arial, Helvetica, sans-serif">The pond can be drained at the appropriate rate.</font></li>
                <li><font face="Arial, Helvetica, sans-serif">Sufficient time will be provided for the drawdown to be effective.</font></li>
                <li><font face="Arial, Helvetica, sans-serif">The pond can be filled prior to the refill deadline.</font></li>
              </ul>
           </div></p>
            <p align="left"><font face="Arial, Helvetica, sans-serif">Maintaining full pool elevation until this date will 
              also minimize the risk of in-lake and downstream fish kills caused 
              by temperature stress and low dissolved oxygen. Fish kills that 
              occur during the warm weather months are often caused by the interaction 
              between water temperature and oxygen depletion in shallow, heavily 
              vegetated lakes (Bennett, 1970). These lakes tend to have elevated 
              oxygen concentrations during the daytime while vegetation is photosynthesizing, 
              yet experience oxygen depletions at night while live plants are 
              respiring and large amounts of decaying organic matter create excessive 
              biological oxygen demand (Wetzel, 1975). Low dissolved oxygen situations 
              are common in numerous small, shallow lakes in Massachusetts. A 
              reduction of the surface water elevation under these conditions 
              could further exacerbate an already critical condition. Temperature-induced 
              fish kills can also be caused by the release of large volumes of 
              warm surface water into a coldwater fishery resource during summer 
              or early fall. One recent example occurred in Coal Mine Brook in 
              Worcester, resulting in a significant kill of brook trout. </font></p>
            <p align="left"><font face="Arial, Helvetica, sans-serif">Part of the Division's management responsibilities 
              is to provide recreational opportunities. Initiating the drawdown 
              after November 1st will minimize impacts on fall recreation by maintaining 
              public boat ramp access and other recreational opportunities. Anglers, 
              seeking to take advantage of stocked trout resources, or warmwater 
              fish species that become more active in the fall, will launch boats 
              or fish from shore. Low water levels can expose boat ramps and hinder 
              safe boat launching. Likewise, exposed mud flats or accumulated 
              dying vegetation can limit access to shore fishing.</font></p>
            <p align="left"><font face="Arial, Helvetica, sans-serif"><i>2. The drawdown must be completed (reach its lowest 
              elevation) by December 1st.</i></font></p>
            <p align="left"><font face="Arial, Helvetica, sans-serif">Amphibians, reptiles and other aquatic organisms need 
              to be able to move to deeper water before ice formation and substrate 
              freezing. Completion by December 1st will also allow aquatic mammals 
              to locate alternate lodge sites and for beaver to relocate food 
              caches before ice formation.</font></p>
            <p align="left"><font face="Arial, Helvetica, sans-serif"><i>3. Lake refill must be achieved by April 1st.</i></font></p>
            <p align="left"><font face="Arial, Helvetica, sans-serif">This refill date will ensure that the resource is 
              impacted for the shortest time period while still allowing the drawdown 
              to be effective. Establishing stable pool elevations by April 1st 
              will provide suitable spawning habitat for littoral spawning fish 
              species. Also, spring traditionally signals the beginning of the 
              fishing season for most Massachusetts anglers pursuing both cold 
              and warmwater fish species. Many ponds are also scheduled for trout 
              stocking in the early spring. For the same reasons previously described, 
              access to public boat ramps (for boats and stocking trucks) and 
              shoreline fishing must be maintained.</font></p>
            <p align="left"><font face="Arial, Helvetica, sans-serif">4. The drawdown rate must not exceed 4 cubic feet 
              per second per square mile of drainage area (cfsm), as measured 
              at the outlet structure, or must not exceed three inches of lake 
              elevation change per day, whichever results in the lower downstream 
              flow rate. Once the drawdown level has been achieved, lake outflow 
              must equal lake inflow. During the lake refill period, 0.5 cfsm 
              must be maintained at the outflow.</font></p>
            <p align="left"><font face="Arial, Helvetica, sans-serif">A major biological concern and priority for the Division 
              is protecting instream flows for fish and wildlife resources. Working 
              in conjunction with researchers at Cornell University, the Division 
              is utilizing the target fish community approach to assess stream 
              fisheries resources and establish restoration goals in flow-stressed 
              streams. An important component of restoration or maintenance of 
              any stream fish community is the establishment of seasonal stream 
              flow requirements. In the absence of site-specific stream flow data, 
              we utilize the United States Fish and Wildlife Service Aquatic Base 
              Flow (ABF) Policy to protect fish and wildlife resources.</font></p>
            <p align="left"><font face="Arial, Helvetica, sans-serif">The ABF Policy focuses on measuring the flows in healthy, 
              unregulated streams and rivers in New England to determine average 
              seasonal flows for the region. Seasonal recommendations, from typical 
              low summer flows to typical spring runoff (referred to as the natural 
              hydrograph) can then be applied during the appropriate time of year 
              in regulated resources or in instances where water withdrawal or 
              manipulation is proposed. The seasonal ABF recommendations are 0.5 
              cfsm in the summer, 1.0 cfsm in the fall/winter, and 4.0 cfsm in 
              the spring.</font></p>
            <p align="left"><font face="Arial, Helvetica, sans-serif">Most drawdowns are conducted during the winter for 
              vegetation control. This creates flow rates that will be greater 
              than the winter ABF recommendation during pond drawdown and less 
              that the winter ABF recommendation during refill. The drawdown rates 
              listed above, although outside the value for the winter ABF recommendation, 
              will maintain stream flows within the range that would be expected 
              in the natural hydrograph.</font></p>
            <p align="left"><font face="Arial, Helvetica, sans-serif">Providing the flows listed in the performance criteria 
              will prevent the stream from going dry during pond refill, minimize 
              downstream erosion and prevent fish stranding in the pond.</font></p>
            <p align="left"><font face="Arial, Helvetica, sans-serif">References</font></p>
            <p align="left"><font face="Arial, Helvetica, sans-serif">Bennet, G. W. 1970. Management of lakes and ponds. 
              Van Nostrand ReinholdCompany, New York, NY. </font></p>
            <p align="left"><font face="Arial, Helvetica, sans-serif">Wetzel, R. G. 1975. Limnology. W. B. Saunders Company, 
              Philadelphia, PA.</font></p>