Salt Creek Floods in Lincoln
The Capitol Building from the Salt Bottoms - 1973
Eleven creeks converge with Salt Creek in the vicinity of Lincoln. They are: Oak Creek, Stevens Creek, Middle Creek, Antelope Creek, Elk Creek, Beal Slough, Haines Branch, Cardwell Branch, Lynn Creek, Deadman's Run, and Little Salt Creek. Combined, they drain over 1000 square miles of land area. With so much land draining into one locale, Salt Creek has caused frequent damage in Lincoln in the past. One hundred floods have been recorded in Lincoln since 1900: 17 major floods and 30 moderate floods, with the rest being minor flood events. This may sound like a large number of floods - it is; however, it is also important to note that each creek and tributary has the potential to flood on its own due to an intense localized rainfall event. For example, Deadman's Run washed out a bridge on Cornhusker Highway in 1966, a year which barely registered any significant rise in the Salt Creek levels. The floods of 1908 and 1950 were the two worst floods of record for Salt Creek in Lincoln in terms of damage. Since then, flood losses have been greatly reduced through the construction of dams and other structural techniques like channelization.
Salt Creek flows to the northeast until it empties into the Platte River near Ashland. Ashland has also had an extensive history of flooding because the Platte, Salt Creek, Wahoo Creek, Silver Creek, and smaller tributaries converge near that City's boundaries. Ice jams are not significant sources of flooding on Salt Creek because the current is generally too swift; heavy rainfall events from March through September have been the most frequent cause.
The first major flood in Lincoln recorded in the newspaper was July 6, 1908. This event was caused by nearly seven inches of rain, with 2.5 inches coming in one 2-hour period. Water was two feet deep on West O Street between 12th and 14th Streets, but O Street was covered from 8th Street East to 24th Street West. The entire Antelope valley was flooded to G Street. Nine people were killed, many houses were destroyed, and 1000 people were made homeless. The peak discharge (rate of flow) was estimated at 30,650 cubic feet per second (13,755,720 gallons per minute); for reference, the average flow for early April is only 140 cfs.
The entire eastern third of Nebraska was flooding in May, 1950, and Salt Creek was no exception. The widespread flooding killed fourteen people and caused nearly $65 million in damage in the Salt, Nemaha, and Blue river basins. The Nebraska legislature provided $500,000 and the Federal government added an additional $250,000 to be used toward response and recovery. In Lincoln, Salt Creek reached a maximum crest of 26.05 feet on May 9th with a discharge of 27,800 cfs (12,476,640 gallons/minute). As high as this was, it was exceeded the very next year when Lincoln recorded a record-breaking crest of 26.15 feet on Salt Creek on June 2, 1951. The discharge was 28,200 cfs (12,656,160 gallons/minute). Although damage accounts were not available for this flood, levees were breaking in Ashland, so it must have been considerable.
The Corps of Engineers built ten dams in the Salt Creek watershed in the 1960s, and the Soil Conservation Service (now the Natural Resources Conservation Service) built thirty smaller upstream dams which have had an impact on flooding on Salt Creek. In Lincoln, the Corps of Engineers also constructed a levee system from Superior Street to Calvert Street, channel stabilization projects on Antelope Creek and Deadman's Run, and channel improvements on Salt Creek. On Oak Creek, a levee was built southwest of the Lincoln Municipal Airport, and the channel has been improved from its mouth to Interstate 80. The City of Lincoln has not had a major damaging flood since all these projects have been completed.
Salt Creek also assisted in making the Midwest flood of 1993 one of the worst ever to affect the United States. Following repeated heavy rainfall events, Salt Creek swelled to a level surpassed only by the 1908 flood. The peak stage was 26.52 feet with a discharge of 28,400 cfs (12,745,920 gallons per minute). Portions of the Devaney Center, the University of Nebraska at Lincoln's sports auditorium constructed close to the Creek, needed to be sandbagged for protection. However, the storage of Corps of Engineers flood control lakes with names like Wagon Train, Stagecoach, Branched Oak, Conestoga, and Pawnee kept enough water back that there was not a great deal of flood damage in the City. To the east of Lincoln, Stevens Creek rose high enough to force the closing of Highway 6 and caused damage to some commercial buildings in that location. However, since it joins Salt Creek downstream of the gauge, the increased flow of Stevens Creek would not figure into the discharge information at Lincoln.
Even though so much money has been spent trying to control flooding in Lincoln, the City still remains vulnerable to flood events. One of the most unfortunate flood control initiatives in Lincoln is the Salt Creek levee. Fill material brought in and compacted to make the levee was high in calcium, a mineral that erodes and dissolves in direct contact with water. Called "dispersive clay," this material soon developed cracks and holes, resulting in the loss of mass within the levee material itself. In addition to the levee material, it was not built high enough to meet federal guidelines for protection to the 1% chance per year (100-year) flood. As a result, even if appropriate materials had been used to build the Salt Creek levee, it still would not be high enough to take the protected area off of the floodplain maps. The Corps of Engineers later decertified the levee as providing 100-year protection when the agency noted the dispersive clay and elevation problems. This meant that development directly adjacent to Salt Creek which had been constructed near the levee was no longer out of the floodplain. Some of the most noteworthy developments in this flood-prone area are the high-density shopping centers at 27th Street and Cornhusker Highway.
As with all expanding communities, the challenge will be for Lincoln City officials to not repeat the same planning mistakes which have placed so many Lincoln residences in the floodplain. University Place of Deadman's Run, Russian Bottoms along Salt Creek, and the Ramone and Clinton neighborhoods of Antelope Creek are all examples of developments which are vulnerable to flood damages. As a result, as flood damages occur, impacted residents demand that their city officials to do something about it. Often, this places a city in a difficult situation, which only gets worse over time as more floods cause more damages if nothing is done. On one hand, the City has allowed the development to take place and is usually seen as the government entity to resolve the problems it has created. In addition, homeowners are faced with filing floodplain development permits to improve their homes, and future buyers will be required to take out a flood insurance policy to cover a federally-backed mortgage. But on the other hand, even if a city decides to build something to reduce flood damages, it is always extremely expensive. For example, the proposed Antelope Valley project in Lincoln has an ever-escalating price tag of $260 million. Even though flood control is only a portion of the costs (other costs are to acquire impacted lands/properties, construction of roads and bridges, and others), it still points out that good planning to start with saves money in the future. Depending on the source of funding for the Antelope Valley project (if found), the costs of correcting poor planning could be borne upon residents of the City of Lincoln, Lancaster County, Natural Resource District, and/or all federal taxpayers.
Some neighborhoods in Lincoln were not in the floodplain when originally developed - it was only through increased runoff from continued development upstream that they became flood-prone. If the City had allowed development according to a "future conditions" floodplain map in order to assume that a watershed would continue to develop in the future, perhaps some of these flood problems could have been avoided. Such a map was available to the City when the Corps of Engineers completed a "fully developed scenario" in its Flood Information Study for Antelope Creek and Deadman's Run in 1966. However, the science of floodplain mapping and the politics of floodplain regulations are two entirely different realities. Future conditions mapping for regulation purposes is a relatively new concept in the arena of floodplain management. Still, as Lincoln continues to sprawl into adjacent watersheds such as Stevens Creek to the east, it would be wise to use the lessons learned from other watersheds in Lincoln as a guide. Every drop of increased runoff in any portion of Lincoln ends up in Salt Creek.
Communities active and enrolled in the National Flood Insurance Program are in charge of regulating all development in their floodplains. A common scenario in Nebraska is when a developer develops a flood-prone property, then leaves it up to the community to manage. Developers really care about building structures and are concerned when communities try place restrictions on them in relation to where they can build. A common cry is that placing restrictions on building will only increase the cost of construction for everyone in the city. While it may be true that some restrictions may increase the cost of housing, construction in the floodplain with little regard for the flood threat is short-sighted and only serves to repeat the same harsh lessons already learned in some portions of Lincoln. If property values are of concern, developing flood-prone areas as open space and parkland should raise the property values of homes adjacent to these open spaces. Furthermore, this will also minimize the future flood threat as there will be no structures to flood in the future. Working with developers and enforcing their own floodplain management ordinance is one of the easiest ways a community can reduce future flood vulnerability. On the other hand, if developers have too much control over the community's elected board officials, the stage is set for continued flood problems in the future.
To complicate matters, if a city decides to undertake a flood control project, it may only partially resolve the problem or even make it worse. For example, Holmes Lake stores floodwater for Antelope Creek; however, even though Holmes Lake does have the capacity of holding back a large quantity of water, there is a large area of developed land in the floodplain (including some University property - the Beadle Center was built on fill to bring it high enough so that it complied with Lincoln's floodplain ordinance). A heavy enough rain in the right location will still cause residential flood damages downstream of the dam. In some cases, a flood control structure can exacerbate flood problems if it is engineered without a master study of the entire watershed. For example, let's say that a large dam is built on Stevens Creek to hold back floodwater. If the peak flow released from this dam coincides with the natural crest of floodwater coming down Salt Creek, that dam will increase the flood problem where Stevens Creek and Salt Creek join. Fortunately, the Lincoln/Lancaster County Planning Department has met this potential problem with the development of a comprehensive master watershed study.
Another piece of good planning in Lincoln has been the preservation of Wilderness Park as open space. Not only does this area retain floodwater with little or no impact to development, but it also provides other benefits such as habitat preservation; recreation for horseback riding, hiking, and biking; and education. Riverside trails have become popular in the last ten years, and it is one of the best ways to maximize benefits while reducing flood vulnerability.
Lincoln is a prime example of why floodplain management is needed. Floodplain management is loosely defined as managing resources so that a community can still grow while the environment can still thrive and the river can still flood. There are very few decision-making arenas where actions taken have such a far-reaching effect on such a broad range of interests. With an extensive history of flooding, development in Lincoln has been - and continues to be - at risk. Yet with sound planning and some good mitigation projects, the City can reduce existing flood exposure and prevent new problems from starting.