Monday, January 16, 2017

A “Birds Eye View” of a portion of the Long Lake Minor Watershed!

Special thanks to the Marie & Tom Hass group who flew over and snapped pictures in early November 2016 after the leaves were down.  Marie’s family home is on Crystal Beach on the east side. She grew up on Long Lake. They were helping explore from the air to see if there was a visible river connecting some of the lakes in our Long Lake Minor Watershed.  Older MN maps show a river connecting Sweitzer and Mud / Long.  It wasn't possible  last autumn to tell from a boat on Mud Lake as fallen trees and high brush at the north end limited visibility and any passage.  

The first photo below is Rockwell Lake with visible wetland/water between Sweitzer Lake on right.  Long Lake is at the top right.  You can see Mud Lake in the middle of the picture, separated from Long Lake by Hwy 34 where a culvert allows water to flow year-round.  Sweitzer has a smaller culvert where water flows toward Mud/Long year-round.  No surface water connection is visible between the water bodies currently;  just wetlands.

Darrin Hoverson, our local MN DNR Hydrologist, gave an excellent Long Lake Watershed power point presentation at our June Annual Meeting (view  here).  Darrin answers additional questions below on the groundwater connections.  

Darrin explained that the Long Lake Minor Watershed system of lakes is connected through groundwater and, at times, the surface water, when waters get high.  Sweitzer Lake is near the top of the surface- and ground- watershed.  Generally the water flow direction flows towards Mud Lake and then into Long Lake.

The green lines on the 1st map below shows an area just north of Sweitzer Lake where the four minor basins meet.  Surface water would flow towards those four basins; Deer/Ida, Ingram/Potato, Fish Hook, and Sweitzer/Long.  Much of this area does not have a connected surface for water to flow, but water will infiltrate into the ground then move as groundwater.  There is a lot of water stored in the ground.  When water flows through the culverts in late winter from Sweitzer and Mud (after no liquid precipitation has fallen) this is known as base flow.  The volume of water is close to the amount discharging from groundwater (springs) into this surface water system.  We are able to see the flow direction for the surface water in red in the 2nd map below with the 2-foot contours map overlay.  The flow direction is from Rockwell, Sweitzer to Mud, then Long.  When the county Geologic Atlas comes out in the next couple years, Darrin says we can learn more about the deeper groundwater connections.

No comments: