HomeMy WebLinkAbout1993-07-26 DNR Ltr to BRAA Re Wetland Design • •
STATE OF s-robitar
DEPARTMENT OF NATURAL RESOURCES
PHONENO. (612) 296 -5200 FILENO.
DATE: July 26, 1993
Joseph Anderlik
Bonestroo, Rosene, Anderlik and Associates
2335 West Highway 36
St. Paul, Mn. 55113
Dear Joe,
Enclosed is a copy of a brochure written by the Wetland Policy
Committee of the Section of Wildlife. It describes the kind of
features we feel are important when designing a wetland from scratch.
The fact that it discuses excavation techniques rather than
impoundments makes little difference so long as the end product is the
same.
As we discussed, my major concern is not to negatively impact the
wetland at the end of the system by allowing to much water to drain
into it. There are several reasons for this including the quality of
the water and the general change in the type of the wetland if the
hydrology changes markedly as a result. It is a very nice wetland as
it is.
Also the fact that the wetland that is "flooding" the Hall property is
within it natural boundaries makes me even more sure that I should
proceed with great caution. The evidence I was able to see during my
site visit is that this wetland has been this high before and will
likely be again. It appears that it is currently near it's ordinary
high water level now and due to weather conditions has stayed that way
longer than what the Hall's feel is normal. The time and duration of
such occurrences has likely changed due to changes in the surrounding
land use but the fact remains that wetlands in the area fluctuate
greatly in elevation over time. The hand dug ditch supports that
contention also. The Halls are not suffering any great damage that I
can see as a result of existing conditions. They have simply taken
advantage of low water levels to expand their lawn and now nature is
taking it back for a time. The real reason for this problem is that
not enough on -site storage was designed into the plat. In fact I could
find none besides the pond to the west of the Hall residence.
AN EQUAL OPPORTUNITY EMPLOYER
. . .
(2)
As we discussed I am prepared to explore options that allow for
storage on Bayport WMA so long as I am convinced that there will not
be any additional water discharged into the wetlands at the end of the
drainage way. This will require construction of new wetlands along the
drainageway that will hold back the overflow while hopefully providing
additional wildlife habitat diversity. This is a very difficult thing
to accomplish because stormwater holding ponds do not generally
provide a very stable water regime and this impacts the wetland
vegetation. this will likely require active water management by the
City under a carefully considered set of parameters. It may not be
possible to prevent the wetland from reaching current levels at all
times no matter what plan we might settle on.
I am looking forward to our meeting on Monday.
Sincerely
Vrt/C/41--
Tim Wallace
Area Wildlife Supervisor
5463 West Broadway
Forest Lake, Mn. 55025