BY ED FELIEN
In one or two months Barr Engineering will release its study of flooding on Lake Hiawatha at a public meeting.
Readers of Southside Pride might remember “Return to Mud Lake” from the March 2016 Nokomis and Riverside editions of Southside Pride in which we wrote how Barr Engineering was studying the effects of pumping water off the golf course into Lake Hiawatha. The Department of Natural Resources has warned that the current amount of water being pumped into Lake Hiawatha exceeds the allowed amount. Barr will answer the question: “What would happen if we turned off the pumps?”
Anyone who lives in the low-lying area around Lake Hiawatha or has played on Hiawatha Golf Course will tell you that the ground is saturated. The water table is very high because Minnehaha Creek has deposited silt on the creek bed and in Lake Hiawatha. It was a mud hole and a slough when Theodore Wirth dredged Lake Hiawatha in 1929 to a depth of 33 feet. He must have also dredged Minnehaha Creek because the level of the lake was 4 to 6 feet lower then than it is today. Currently, the depth of Lake Hiawatha is only 10 to 13 feet but the water level is 4 to 6 feet higher than it was.
The water level of Lake Hiawatha is totally dependent on the level of its exit channel. If the exit channel of Lake Hiawatha, the creek from 28th Avenue to Minnehaha Falls, was dredged and 4 feet of accumulated silt were removed, the water level of Lake Hiawatha would be lowered by 4 feet, and, most importantly for the homeowners in the low-lying areas around the lake, the water table that increases the danger of flooding would be lowered by 4 feet.
Barr Engineering will present its findings at a public meeting after it has met with homeowners in the area to tell them the results of their study. It has seemed self-evident and obvious to us that if they turned off the pumps virtually nothing would change for the homeowners. Pumping water out of the saturated ground into Lake Hiawatha does nothing to lower the water table. The water just seeps back into the ground. The water level of Lake Hiawatha and the level of the water table of the low-lying neighborhood surrounding it can only be lowered by lowering the exit channel (the creek as it leaves Lake Hiawatha on its way to Minnehaha Falls) at 28th Avenue.
There is a grit chamber at the entrance to the storm sewer on the west side of Lake Hiawatha, but the lake level is so high it is impossible to clean it, and, consequently, all the trash from as far north as Lake Street washes into the city sewers and ends up coming out the storm sewer at Lake Hiawatha.
Dredging the creek would not be prohibitively expensive. From “Return to Mud Lake”: “I wrote to Tillges Excavating and asked how much they would charge to dredge a creek, digging a trench 4 feet deep, 4 feet wide and 1.3 miles long (about the distance from 28th Avenue to the Falls). They said, ‘It would all depend on the conditions. For example if it’s wet conditions you could get as high as 100,000.00 or even higher. I just bid a dig for electric trench one mile long and that bid was for dig and back fill that estimate was 85,000.00. I’d guess if it’s good conditions you’d be looking at 55,000.00 that would be also be spreading out the excess dirt in a reasonable distance from the creek bed.’ ”
