Thomas Creek dam

A photo provided at the PMRNRD and U.S. Army Corps of Engineers Papillion Creek Basin flood mitigation preliminary study meeting on Tuesday. The photo shows a portion of a flood pool for a proposed dam on Thomas Creek reaching into Washington County. The dam itself, if ultimately deemed a viable and funded flood mitigation project, could be located just west of state Highway 133 and just north of state Highway 36.

A proposed dam on Thomas Creek could affect Washington County landowners, according to a preliminary study on flood risk and mitigation in the Papillion Creek Basin. The Papillion Creek Basin includes much of Douglas, Sarpy and Washington counties.

The Papio-Missouri River Natural Resources District (PMRNRD) and the U.S. Army Corps of Engineers held a public meeting Tuesday at UNO's Mammel Hall, a meeting which marked the midway point of the two organization's joint study analyzing possible flood control measures in the basin. The study includes multiple mitigation strategies such as dams, flood walls and levees in and around Omaha as well as elevating and flood proofing buildings.

The dam proposed on Thomas Creek could be located just west of state Highway 133 and just north of state Highway 36. While the dam itself is not in Washington County, the flood pool could reach across the Washington and Douglas county line, according to preliminary, and yet undetailed, designs provided at Tuesday's meeting.

PMRNRD officials told the Enterprise earlier this year that no dams were planned for Washington County. Though the Corps analysis currently considers the benefits of a dam on Thomas Creek to outweigh the costs for the Papillion Creek Basin, it does not guarantee construction. Construction on any projects considered viable in the final study could start in 2025.

Ted Japp represents all or parts of Washington, Burt, Dakota, Douglas and Thurston counties on the PMRNRD board. He said he knows the landowners near the proposed Thomas Creek dam are in strong opposition to construction.

"I would strongly urge you to create a flood control model for the Thomas Creek, Little Papio Creek that does not affect the (Thomas Creek dam) landowners," he said to Corps members during the meeting.

Several Washington County residents attended the meeting and questioned building a dam on Thomas Creek as part of flood control for areas continually developed in the basin's 500-year flood plain in Omaha.

"Why is all this building happening?" Kennard resident Jason Cloudt asked during a public comment portion of the meeting. "I've asked the Corps, I've talked to the NRD, 'Well, we don't control that.' Well, let's put some effort into controlling where the building is happening instead of continuing to build where we think we're smarter than mother nature."

Kennard resident Robert Harper said farmers north of Omaha have invested in terraces to help control runoff into Thomas Creek, which flows into the Little Papillion Creek near 90th Street in Omaha. In a letter to the Corps last year, Harper and his wife, Amy, addressed their concerns of continued development in the basin's flood plain. The letter was included in an appendix of the preliminary study.

"We put in miles of terraces and waterways and implemented farming practices to minimize runoff and erosion. Douglas and Sarpy counties were to do their part by limiting development in the floodplain to minimize future risk," the letter said. "Where are we now? The urban counties can't say no to developers and have continued to allow building on the banks of the Papio."

The Corps estimates there is $1.9 billion worth of property in the basin's 500-year floodplain, which includes homes, commercial and industry development. Damage in the floodplain could be more than $19 million, according to the study, and flooding could affect 25,000 to 59,000 people depending on the time of day.

The cost of the proposed Thomas Creek dam could be about $26 million dollars and generate about $45 million in benefits, the study says. The Corps study deems a flood control project viable if its benefits, such as flood avoidance and reduction in emergency response, outweigh its costs, such as construction and real estate costs.

Tiffany Vanosdall, the Corps project manager for the study, said more analysis will be conducted and additional costs and benefits, such as the costs to move utilities, would be added to the study that is still over a year from completion.

"The stage that we're at right now mostly includes construction costs," she said. "We've included contingencies for things like utility line removal, but they haven't been costed out in terms of the contingency that's been added to cost estimate at this point."

The study is currently under independent review by a third party.

"We basically provide the report to an independent third party," Vanosdall said. "They have reviewers that review the document and then make comments. That is all made public, so you will get to see what comments from that independent external review."

The review and comments should be available to the public in March, she said.

Steve Schulz, a UNO professor researching economics of flood mitigation projects, said during the meeting that he's worked with Corps offices in Washington, D.C. to analyze structural inventory studies done by the Corps on other projects. He said the potential economic damage associated with home, business and other structural inventory analysis is the "achilles heel" of the Corps flood mitigation studies.

"In other words, if you don't get the estimation of the flood damage potential correct, all those cost-benefit analyses are incorrect," he said, adding he hopes the Corps and NRD's Papillion Creek Basin study further explains its structural inventory methodology more than is done so far in the study.

Amy Harper said the Corps should consider the cost of removing farmland from use, and the potential economic benefit that farmland brings to local residents and municipalities.

"I think you should have to include that loss of economic impact with your figures," she said.

The impact of dams on county farmland has been a significant reason the Washington County Board of Supervisors, in addition to land owners like the Harpers, have said no to dams in the county.

In December 2018, the board of supervisors passed two resolutions and approved a letter opposing two studies and the potential for dam construction in the county.

"We believe alternative means of flood control are more suitable and would not negatively impact the agricultural economy of Washington County," the letter said.

Vanosdall said public comments, the independent review and additional analysis are taken into account in the study.

"Based on those comments a decision is made, do we proceed with doing more analysis, more design on the alternatives we've laid out, or do we have to modify things," she said.

The Papillion Creek Basin preliminary study can be found on the Corps and PMRNRD websites. Comments can be sent to the Corps at until Jan. 3.

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