BY ED FELIEN
Over the years the water table in the neighborhoods around Lake Hiawatha and Lake Nokomis has risen because of silt brought downstream in Minnehaha Creek. The depth of Lake Hiawatha when it was dredged by Theodore Wirth in 1929 was 33 feet. Today, because of the accumulation of silt, the depth is probably 10 feet, according to informal amateur estimates with a depth finder. There have been no official measurements by the park board or The Minnehaha Creek Watershed District. Lake Hiawatha and Lake Nokomis are higher today because if you keep pouring sand into a bucket of water the water level in the bucket is going to rise.
The land around the lakes is porous. The bottom land was considered unfit for housing at the turn of 20th century. A map from 1905 shows housing built all around the area but not in the areas adjacent to the lakes: https://southsidepride.com /the-return-to-mud-lake/. But the dredging by Theodore Wirth lowered the water table and made the area habitable. I grew up on the Mud Flats at 42nd Street and 29th Avenue.
Eighty years after the original dredging, the water table is rising to the level that Wirth found it. Pumping water out of the water table on the Hiawatha Golf Course will only temporarily lower the water table. The ground is so porous that the water that gets pumped into the lake returns to the groundwater under the golf course in a very short time.
Officials from the park board and the city met with homeowners whose basements flood during heavy rains. The pumps offer some relief, and the officials assured the homeowners that they would do everything they could to continue pumping so as to make their homes livable.
It’s a little like a Sword of Damocles hanging over the heads of the homeowners. It hangs by a thread. It could fall at any moment and destroy their homes. They are saved only by the care and generosity of indulgent public officials. Of course, the original Damocles was a flattering courtier seated under the sword and warned that any more obsequiousness would spell his doom. In an ironic reversal, it is the flattering obsequiousness of constituents that convinces officials to save the homeowners from destruction.
Pumping water out of the golf course is not the solution. It is a temporary expedient that does nothing to solve the basic problem of a high water table.
To return to the analogy of the bucket. If there is a hole in the bucket, water coming into the bucket cannot rise any higher than the hole. The Minnehaha Creek outlet at 28th Avenue acts as the hole in the bucket. Water from Lake Hiawatha flows out through that exit. The bucket is not a perfect analogy because most buckets are not as porous as the basins holding the water of Lake Hiawatha and Lake Nokomis. The water level in the lakes is almost at the same level as the water table in the sandy loam surrounding it. So, if you drilled a hole a little lower in the bucket, if you dredged 4 feet of silt from Minnehaha Creek at its exit from Lake Hiawatha at 28th Avenue to the falls (there is a gradient of more than 12 feet in that distance), then you would lower the level of Lake Hiawatha and the water table in the surrounding neighborhoods by 4 feet.
Currently, there is standing water in the yards of the homes around Lake Nokomis. Why is that? Isn’t it because the ground is saturated. And the ground is saturated because the water table is too high. This is not just an aesthetic problem or a mild inconvenience. The saturated ground will freeze in the winter. The ice will expand and it will crack foundations.
Steffanie Musich, the park commissioner who is directing the expensive and unending studies of the Creek and Lake Hiawatha, isn’t convinced there is a problem for the homeowners, and she is concerned about how lowering the water level of the creek would affect the habitat of muskrats living downstream. She would like to see more studies. I think after spending another couple of hundred thousand dollars they might discover that water runs downhill and it expands when it freezes. But it could be years before they reach those astonishing conclusions.
For those who prefer the natural look, who would like to see nature restored, particularly in areas where you don’t live, I will be proposing an Environmental Impact Statement that will stop you from shoveling snow off your driveway for fear of disturbing the natural habitat of snow snakes. If you disagree … If you think shoveling snow doesn’t really harm the ecology of winter, then why would you object to shoveling the sand and sediment that has collected on the bottom of Minnehaha Creek over the years?
