March 2006

The DNR communications team works with agency experts to develop the weekly questions and provide the answers. This feature addresses current DNR issues, interesting topics, or the most frequently asked questions from around Minnesota.






If a lake or river is added to the impaired waters list, how long does it take for that body of water to be removed, if ever?

The length of time it takes to clean up a lake or river and remove it from the impaired waters list depends on the present condition of that body of water. After listing, the first step to removing a body of water from the list is to establish a Total Maximum Daily Load, or TMDL. TMDL sets the standard, identifying the total amount a pollutant that can be discharged into a body of water without impacting water quality. TMDLs identify pollution sources as well as the amount of pollution that can safely come from each source. Once the TMDL is completed, a plan is developed to address and reduce the pollution sources. Completing both the TMDL and the implementation plan can take anywhere between about eight and 14 years, but once they are approved by the U.S. Environmental Protection Agency, the water body can be removed from the impaired waters list. Clean up begins after the TMDL and implementation plan are completed. The amount of time it takes to "clean up" a water body is quite variable depending on the pollutant, types of activities conducted, need for changes in law, amount of available funding, etc. Additional information is available on the Minnesota Pollution Control Web site at:

Steve Colvin, DNR Ecological Resources


It is not uncommon to find antlers lying on the forest floor in the spring. Why do buck deer, bull moose and other antlered species shed their antlers?

Annual cycles in deer antlers are related to the changing seasons. Deer have adapted their physiology and behavior to respond to seasonal changes, including antler growth and shedding. The environmental cue that regulates antler growth is the amount of day length, or photoperiod; the physiological cue is the hormone testosterone. Simply put, the changing day lengths are sensed by the eyes, which send this message via the optic nerve to the pineal gland that is located at the base of the brain. This triggers changes in hormone production. The declining day length in late fall and early winter causes a decrease in testosterone, which results in antler shedding. The actual process of antler shedding involves the formation of a thin layer of tissue destruction that forms between the antler and the pedicle, called the abscission layer. The degeneration of the bone-to-bone bond between the antler and the pedicle is considered to be the fastest deterioration of living tissue known in the animal kingdom.

Michelle Carstensen Powell, natural resource specialist-CWD


Every spring the DNR imposes burning restrictions for counties throughout Minnesota. Why are they needed and what is their purpose?

The DNR issues burning restrictions to help reduce the potential for personal property damage and injuries resulting from the large number of spring wildfires. A majority of these wildfires occur as the result of burning vegetative debris from yard cleanups. As the snow melts, the dead, dry vegetation becomes an instant fuel source. Any accidental or managed fire that escapes control could spread quickly and uncontrollably across the landscape, including residential areas. The restrictions are set to coincide with this time of the year, when the fire potential is the highest and historically when most fires occur in Minnesota. Burning restrictions may also be implemented at other times of the year during drought conditions, for example. Restrictions typically last 30-45 days.

Jean Bergerson, Minnesota Interagency Fire Center information officer


When the 2006 fishing season opens May 13, anglers may once again fish for walleye on Upper Red Lake. What did the DNR and other organizations do to get the lake ready for the opener?

A successful restocking program along with total protection for walleye, enabling them to grow and mature, has assured excellent angling opportunities this spring on Upper Red Lake. Minnesota DNR Fisheries and Red Lake Band biologists have developed a management plan that will limit the harvest within sustainable levels, and allow them to measure and react to impacts on the walleye population. A citizen advisory group, representing a number of local and statewide organizations, helped the DNR set fishing regulations. These will protect the fishery and maximize recreational opportunities for both summer and winter angling. DNR Divisions of Trails and Waterways and Parks and Recreation, the Upper Red Lake Area Association and Waskish Township made major improvements to the public water accesses, camping and recreational facilities in the Waskish vicinity. Private resorts, campgrounds, bait shops, and other related businesses have enhanced their facilities in preparation for the 2006 opener.

Gary Barnard, DNR Area Fisheries manager, Bemidji


DNR Question of the Week Archive