I remain fascinated by Governor Dennis Daugaard's decision to close I-29 and turn Exit 4 into a levee to divert flood water from the Big Sioux River into McCook Lake. While the action proved unnecessary—the Big Sioux crested earlier and lower than expected, leaving the Interstate dry—I subscribe to Lt. Gov. Matt Michels's statement that in disasters, we prepare for the worst and hope for the best.

But consider why the Exit 4 levee turned out to be unnecessary. We got less rain than forecast last Wednesday and Thursday. The Army Corps of Engineers helped out by reducing releases from upstream on the Missouri, lowering the total water level at the Big Sioux–Missouri confluence at Sioux City. And a levee gave way upstream on the Big Sioux near Akron, Iowa. That breach Tuesday night poured water out on a lot of surrounding farm land and some houses in Akron. It spread the river out, slowed it down, and lowered the height of water rushing toward North Sioux City.

The Governor faced a hard choice this week. The data before him led him to decide that shutting down I-29 (costing truckers alone $100 to $200 a day) and diverting floodwater through the McCook Lake residential development was the best balance of costs and benefits the state could get. Yet physics and hydrology appear to have made a different choice, sacrificing farm land upstream. While the analogy is imperfect, there are shades here of the wetlands discussion we had earlier this week: let water remain in the farm fields longer, and you reduce the intensity of flooding downstream.

To say the Governor chose to sacrifice McCook Lake houses may not be entirely accurate. A local resident studies the topo maps and the lay of the land in the neighborhood and tells me McCook Lake lies in the natural path flood waters of the magnitude predicted would take to the Missouri. According to my observer on the ground, that line of Hesco baskets under the Exit 4 overpass might not have single-handedly flooded out McCook Lake; it simply might have prevented the spillage from also washing out the rest of North Sioux City. So part of the story here could be that, as with Fort Pierre and Dakota Dunes, folks around McCook Lake chose to build in an area prone to flooding.

But part of the problem was that McCook Lake residents couldn't get a straight answer on just how high the water would get if the water came, naturally or enhanced by emergency engineering. A local resident reports that the county and state did a poor job of giving residents clear information:

Topographical elevation information is widely available from various sources with widely varying accuracy, but all those published and meter-reported values are stated as elevation compared to Sea Level. Yet these paid government officials refused to reference the common Sea Level elevations, but rather spoke only in terms of the arbitrary "Flood Stage" elevations which are not apparent to community residents. I've been to most local landmarks yethave not seen even one "Flood Stage" monument marker. I've read that one exists in South Sioux City, Nebraska, miles away. Why there is no such marker at the bridge going between Riverside and North Sioux City is a mystery to me. It could be erected cheaply and would be apparent to most adult citizens. Similarly, no such marker is on the pillars supporting the I-29 Interstate highway bridge joining Iowa to South Dakota. Yesterday the flow of auto and pedestrian traffic which went there to observe the water flow by passing through RiverSide park to the Boat Club area was continuous. Again, epoxy painted water-elevation markers on one of those bridge support pillars would quickly become widely known by Sioux-Land residents if that marker existed.

So back to the meeting [Wednesday evening, Dakota Valley High School gym]. When they finally opened it up for questions, the first questioner beat me in asking how to convert common Sea Level elevations to their local "Flood Stage" elevation system. The questioner's question was so popular by frustrated attendees that it actually generated applause! Obviously that super important information had NOT been communicated. I'd spend hours looking for it through I-net research.

Response was so echo entrained that I could not understand it. I asked the person on my right, then the person on my left, then the person behind me. None of the four of us had been able to understand the answer. Talk about lousy communication! [local resident, e-mail to Madville Times, 2014.06.20]

The state also seemed a bit stingy in offering resources to the residents whose homes it was willing to place in greater danger. Local residents waited for two hours Thursday to receive a limit of 20 sandbags. When locals offered to help National Guard crews fill sandbags faster, the Guard chief admitted they had limited personnel but said the Guards had to do the job on their own.

The levee-building and sandbagging around McCook Lake weren't for nothing. But the state didn't provide enough information or resources to help McCook Lake residents deal with the burden the state was asking them to bear for the greater good.

The levee break upstream at Akron further suggests an alternative to the state's response to the Big Sioux flood. With the water slowly receding from the second hundred-year-flood in the North Sioux City area in three years, maybe we should take some time to study where the water went in Akron, how much that damage cost, and whether a system of controllable levee releases all along the river in less populated farmland could provide better flood control than a planned diversion channel across a federal highway and through people's homes.

Or maybe the National Guard should just dredge, widen, and dike the Big Sioux channel through North Sioux City?