FEMA’s New Floodplain Maps in Effect for Hall County & Northwest Grand Island
FEMA released a Letter of Map Revision (LOMR) consisting of seven revised map panels in northwest Grand Island and in Hall County north and west of Grand Island. This LOMR reduces the floodplain and ultimately requirements for flood insurance for 1,600 property owners.
Properties north of Capital Avenue between the Burlington Northern Santa Fe elevated track on the east, Monitor Road on the west, and as far north as White Cloud Road will benefit the most from the reduced floodplain. Houses north of Capital Avenue are now zoned for a 500-year flood event, reduced from a 100-year event.
Property owners in the revised areas should contact their insurance company about shifting their Flood Insurance Policy to a preferred rate policy if they are no longer in the regulatory flood plain and contact their lender to determine if their loan still requires a flood insurance policy. A low-cost preferred rate policy is recommended as additional insurance for property that may still be in or near the revised flood risk areas, as flooding impacts are not covered by other forms of insurance. For details about the impact on flood insurance contact Chad Nabity, Hall County Planning Director at (308) 385-5240.
Project details can be found below and at https://www.floodsafe-cpnrd.org/. For information about the project and the structures that were built to modify the floodplain contact Jesse Mintken, Central Platte NRD Assistant Manager at 308-385-6282.
ELM & TURKEY CREEK WATERSHED
JEO Consulting Group to develop a Watershed and Flood Prevention Operations Plan (WFPO)-Environmental Assessment to address flooding in the Elm and Turkey Creek Watershed at the September 2020 board of directors meeting. JEO’s Plan approach will use a detailed hydrology and hydraulic model complemented with data from the Nebraska Department of Transportation studies, existing topographic surveys, field site visits, public input and 2019 flood event flow input. The model will illustrate anticipated inundation areas from various events, reductions from alternatives, and project screening.
Watershed & Flood Prevention Operations (WFPO) Grants
NRCS has approved three grant applications to pay 100% of the cost for completing a watershed and flood prevention operations plan. In total, the funding available to the Central Platte NRD over the next two years for the three watershed agreements is $2,092,500. Richard Vaughn is the NRCS Watershed Coordinator in the State Office and will be the Government Representative for the projects.
-Wood River Watershed The board selected a joint proposal from JEO and EA Consultants to develop a WFPO to address flooding in the Wood River Watershed. The Watershed Work Plan-Environmental Assessment for the Lower Wood River Watershed Improvement Project will include portions of Buffalo, Hall, and Merrick counties.
-Buffalo/Spring Creek The board selected HDR Engineering to develop a WFPO to address flooding in the Buffalo Creek/Spring Creek Watershed. The Watershed Work Plan-Environmental Assessment for the Spring and Buffalo Creek Watershed Improvement Project is in Dawson County.
-Turkey/Elm Creek A request for bids has been sent out and will be available for consideration at the September board meeting. NRCS will pay 100% of the cost of the new watershed plan up to $742,500.00.
2019 Flood…NRDs Share Experiences
A year has passed since the historic flooding we had in March 2019.
We all remember it. Our NRD along with the Lower Elkhorn, Lower Platte North, Lower Platte South, and Papio Missouri NRDs are all in an agreement to monitor river conditions along the Lower Platte River. We are boots on the ground and sharing our story about the events that unfolded here in our own District and partner Districts. Listen to the Podcast
IMPACT OF FLOOD RISK REDUCTION PROJECTS
The Flood of 2019 embodied Nebraska’s Natural Resources Districts’ purpose to Protect Lives, Protect Property, and Protect the Future. Over 40 flood risk reduction projects have been built in communities throughout the Central Platte NRD to prevent flood water from damaging homes, businesses, and land.
As a result of these projects, the majority of the District from Gothenburg to Columbus was protected by the cyclone bomb storm that hit the state in March.
In the western area of the District, the Buffalo Creek Watershed Structures protected Custer, Dawson, and Buffalo Counties. B-1 Reservoir, the largest of seven structures, was filled to capacity for the first time since it was built in 1983. B-1 held over 2,000 ac/ft of flood water. In 2006, the Kearney Northeast Project was completed. That project included channel improvements on the Wood River and detention cells that also helped protect the City of Kearney this year.
Two major projects protected the City of Grand Island. The Wood River Flood Risk Reduction Project in southern Grand Island was completed in 2004. The left bank levee system is 7.9 miles long and located on the north side of the Wood River. It protected 15,514 acres of residential, commercial, and industrial land uses; including 9,360 people and 3,919 buildings (3,655 residential). The right bank levee system is 4.7 miles long. located on the south side of the Wood River. It protected an additional 1,337 acres of land consisting of mostly farmland.
The Upper Prairie/Silver/Moores Project (near completion) held massive amounts of floodwater protecting 23,000 acres south of Hwy 2 and east of Hwy 281 in Grand Island. The project includes four dry dam sites, one levee, and detention cells that held 5,000 ac/ft of runoff; protecting 2,800 properties in western and northern Grand Island.
Projects in the eastern area of the District also worked as designed. The Warm Slough/Trouble Creek Project,
completed in 1993, helped protect the entire watershed by reducing flooding caused by storm runoff into the
Warm Slough, Dry Run, and Trouble creeks.
Lyndon Vogt, CPNRD general manager, said: “Based on the flows that we saw, the communities in our District benefitted more from the projects than we had anticipated.”
CPNRD partners with local, state, and federal agencies to develop projects in areas that are prone to flooding
Central Platte NRD is comprised of 27 municipalities with varying flood control issues and challenges. There has been a multitude of flood control projects across the NRD ranging from dams to levees, to the clearing of creeks and streams. CPNRD works with landowners and other agencies to minimize damages that cause flooding. Our goal is to use each acre within its capability and to treat each acre according to its needs as set forth in the technical guidelines adopted by the District.
Much of the Central Platte NRD has long been plagued by floods. On the average, there’s a flood every year in some area of the District, with major floods occurring every six to eight years. The land area within the District is unusual in the fact that most of the tributaries of the Platte River run almost parallel to the Platte itself. Consequently, the tributaries span many miles of the flat terrace or bottomlands adjacent to the Platte before emptying into the river.
In the central and western ends of the District, most of the tributaries originate in the uplands where flood control structure sites are plentiful, but then drop off into the flat terrace or bottomlands and meander for many miles before reaching the Platte River. Many of the District’s other streams, such as Silver Creek, Warm Slough, and the North Branch, originate in the flat terraces or bottomlands where there are no sites for flood control structures. Even Prairie Creek has no flood control structure sites except in its extreme upper reaches.
The Wood River has approximately 173 miles of channel meandering through the fertile Platte River Valley. There are numerous flood control structure sites in its upper reaches. However, in the flood of June 1967 on the Wood River, most of the rain contributing to the flooding in the Grand Island area fell east of Kearney where there are few flood control structures sites. Although flood control structures are or could be, of great benefit to this area, total protection cannot be achieved without some form of channel rectification. The Board has adopted, as a general policy, the design and construction of flood control measures on a watershed basis.
The NRD has developed over 30 flood control structures. The plans for these structures have been designed to provide for orderly development of flood control and other related resources activities in watersheds, with each watershed plan encompassing a number of individual project plans in the total watershed development.
FLOOD RISK REDUCTION PROJECTS
Amick Acres Project The Amick Acres Project Improvement Area is located in south central Hall County, just to the west of Doniphan. It diverts flood and drainage water away from the Amick Acres residential subdivision by utilizing part of a county road ditch for approximately 1 mile. The initial cost was $25,000; most assessed to benefiting landowners. Maintenance is done as necessary at an estimated cost of $500-$1,000 annually. Actual costs are calculated and assessed to benefiting landowners.
Buffalo Creek Watershed-Structures Feasibility planning for flood control was completed in the Buffalo Creek Watershed, located in Custer, Dawson and Buffalo counties. CPNRD received approval for cost-share funding from the Natural Resources Development Fund to construct seven flood control structures in the watershed: B-1, B-3, C-5, F-l, F-3, F-5 and F-7. Additional work: B-1: the largest structure, was completed in 1983 along with the supply canal, 1.6 miles of power line relocation and 1/2 mile of county road improvement. In addition to flood control, the project was expanded to include recreation and groundwater recharge. Cracks were identified in the B-1 structure in the fall of 1983. Repair included installing a chimney drain system on the back side of the structure and was completed in 1985. In 1987, the reservoir was opened for day fishing. In 1995, a petition from numerous landowners requested that the NRD discontinue filling the reservoir because they were concerned that the reservoir contributed to high water tables in the c Hydrological studies conducted by the NRD showed that the B-1 reservoir made no significant contribution to the high water tables and that projected groundwater declines had not materialized due to continued strong annual rainfall amounts. However, the request to stop filling the reservoir was granted effective January 1, 1996. In May 2009, the board voted to start filling the B-1 Reservoir in Lexington every other year starting in spring of 2010 and was required to fill the reservoir once every five years to keep the NRD’s water right. In March 2011, the board approved leasing water from B-1, for a one-year basis, to 40-45 individuals who needed 1-15 AF of water. In March 2013, the board voted to start filling the reservoir every year and to get it back to its original concept. The NRD has a diversion right of 4,000 acre/feet of water per year from NPPD to fill the reservoir and there are plans to have the NGPC begin stocking the reservoir within this planning period. F-7: Cracks were identified in the structure and repair was completed in 1990 at a cost of $11,500. Two sites in the Buffalo Creek Watershed north of Lexington were studied to determine their potential as flood control structures. Based on the study, the NRD board determined that construction of flood control structures at those sites was not feasible and that all further planning efforts for the watershed would be discontinued. Operation & maintenance continues for all of the structures in the watershed including dam safety checks. In addition, CPNRD will fill the reservoir periodically with the minimum amount of water to satisfy the project’s Platte River water right.
Cairo Downtown Improvement Project In 2007, the NRD provided $50,000 to the community of Cairo to add a 48” drainage outlet for the Project to divert excess water along the Hwy 11 corridor. The previous drainage system couldn’t handle a one-year rainfall event, which caused overflow ponds and flooding in low areas. The community of Cairo contributed $2 million to the project.
City of Gibbon The City of Gibbon filed a formal request for help with a drainage project. Olsson Associates proposed solutions to the city’s current drainage system including relocating the existing sluice gate, improvements on hydraulic conditions at the outfall and installing an automated sluice gate system. The total cost of the project is estimated at $150,000 and has been added to the Hazardous Mitigation Plan to be considered for Federal funding in the future. In 2008, provided $50,000 to the City for improvements to the stormwater system and the project was completed in 2010. In April 2015, OA reviewed what the City of Gibbon had accomplished towards drainage issues and the additional needs in order to resolve remaining issues. CPNRD staff has facilitated meetings with the City of Gibbon, Buffalo County, and CPNRD to address the remaining drainage problems.
Clarks Floodplain Silver Creek is the major source of flooding in the area. The board approved participation in the Clarks Floodplain mapping study up to $5,000; which is 50% of the expected cost of the study and needed to meet FEMA requirements. The study and funding were added to the 2014 Fiscal Budget.
Clear Creek Watershed Clear Creek Watershed in Polk County encompasses 75,700 acres & has a long history of flooding. A feasibility report for flood prevention and watershed protection was completed in 1978; which lead to the construction of 15 flood control structures completed in the watershed. Funds from the Natural Resources Development Fund were received on 5 of the larger structures. Polk County provided funds to construct additional smaller structures including road structures.
Dams Inventory In 2016, the board approved a contract with JEO Consulting in the amount of $39,500 to conduct an inventory of dams that are one acre or larger within the District. Staff will request the remaining fee of $25,000 through FEMA’s Hazard Mitigation Fund.
Doniphan Drainage In 2015, the Village of Doniphan requested $4,000 to pump standing water from a detention cell located in the city park and into the curb and gutter system. The project was completed in the fall of 2015.
Dry Creek Clearing Project Debris from a wind storm/tornado fell into the Dry Creek channel northeast of Cairo in 1997, prompting a request from landowners for a clearing project. The NRD Board authorized a clearing project. The cost of the project completed in the winter of 1998 was approximately $11,500. Area landowners petitioned the NRD to complete about 21,000 feet of additional clearing; which was completed in the winter of 1999-2000 at a cost of about $42,000. In 2012, a three-mile channel improvement was completed to the west of Central Nebraska Airport and a culvert was added under Gunbarrel Road. Maintenance is completed by the NRD as needed.
Elm Creek/Turkey Creek Watershed A feasibility study was conducted for $125,000 and submitted to the Nebraska Resources Development Fund to request cost share. A community meeting was held in June 2006, on the feasibility study for Elm Creek Watershed Flood Control Project. 130 landowners attended. Olsson Associates’ Plan consisted of a 975-acre flood control and re-regulating reservoir located northwest of the Village of Elm Creek and two dry flood control structures located on Turkey Creek. The reservoir would provide both traditional flood reduction benefits to the Village of Elm Creek and non-traditional environmental benefits including recreation. The Turkey Creek structures would reduce current peak flows to downstream areas. Together, the flood control structures would provide flood protection to the Village of Elm Creek and downstream cropland. The preliminary cost estimate was $22.8 million. The board approved a study with OA to perform a geotechnical investigation and seepage analysis of the area. The study involved the drilling 30 test borings at the reservoir site and adjacent lands to determine if leaching would raise adjacent water tables to a level that would create problems for either cropland or basements. OA developed a preliminary design feasibility study and CPNRD applied for Resources Development Funds. In June 2012, the board again reviewed the project due to a potential new source of funding from the Nebraska Water Cash Fund. The board authorized staff to work with OA, Nebraska Public Power District (NPPD), State of Nebraska & Platte River Program on options to move forward with a project. The proposed project was estimated at 6,800 -12,000 AF depending upon future agreements with a projected cost of at least $35 million. In 2013, the board approved the transfer of funds in the amount of $631,465 that was originally designated for the proposed Elm Creek Re-Regulating Reservoir to the CNPPID’s new J-2 Reregulating Reservoir project; cutting the Elm Creek project from the budget.
Ice Jams In July 2011, the board approved an inter-jurisdictional cooperative agreement on how to deal with ice jams in the Middle Platte River, with the formation of a continual escrow (interest-bearing) account in the amount of $50,000. If an ice jam were to begin, CPNRD would be the first entity to start the process of calling FEMA & NEMA; in which the entire process could be completed in one day. The agreement is signed by seven partners who have deposited $37,000 in an emergency fund to use in the case of an ice jam on the Platte River. In 2016, the board voted to dissolve the existing Platte River Ice Jam Removal Agreement. Instead, the agreement partners plan to develop a working agreement that will focus on emergency preparedness in the event of an ice jam related to flooding and safety education. All funds in the ice jam account were returned to the partners who include: Tri-Basin NRD and Buffalo, Hamilton, Merrick, Phelps, and Kearney counties. Emergency Info on Ice Jams
Kearney Northeast Flood Control Project A cooperative effort involving the City of Kearney, Buffalo County, and CPNRD, was initiated in 1990 due to the expansion to the northeast of the city of Kearney. The expansion has resulted in increased flooding on an unnamed tributary of the Wood River resulting mainly from storm runoff. CPNRD obtained aerial photography and participated in survey work needed for topographic mapping of the affected area. After the mapping was completed in 1991, NRCS conducted a feasibility study to determine what options were available. In 1995, Miller & Associates developed a plan for the watershed; including channel improvements, drop structures, road crossings and a detention cell. Cosponsors shared costs of the project & agreed to do the construction in phases so taxpayers would not have a large one-time impact. To stop a serious erosion problem at the point where water had been entering the Wood River, a drop structure was constructed in 1996 at the cost of $240,000 by the NRD. As part of its bridge replacement program, the County also built a road structure used by the project. The project was completed in three phases: Phase I: The existing channel was widened starting at the drop structure and meandered westerly and south to a point near 56th Street on Eaton Road. Phase III: (Completed before Phase II) In 2000, properties were bought and construction was completed on the detention cells and channel improvements. Detention cells are located 1/2 mile north of “N” Ave and 56th St in Kearney. Construction included 300,000 yards of excavation with a 50 ac/ft storage design for a 100-year storm and a 50 ac/ft storage design for a 25-year storm on the other cell. In 2003, the NRD approved a contract change to complete channel improvements south of the detention cells and to control erosion. There were 800,000 cubic yards of soil excavated to create the channel. Storage capacity is 200-300 ac/ft. Phase II: Consisted primarily of channel improvements from the Phase I channel south to about 39th Street and then westward to Antelope Road. Phase II to Phase III, from 56th Street to Avenue N was completed in the spring of 2006. The total cost of the project was $3.4 million.
Kearney West Clearing Project In the fall of 1999, landowners west of Kearney requested a clearing project to assist them with flooding problems along Turkey Creek, also known as the Platte River North Channel. About 2 1/2 miles were cleared after the request. In 2000, an additional mile was cleared and snagged. Snagging & clearing was done in 2000 on the North channel and again in 2001 at a cost of $8,650. In 2002, the NRD was notified that the North Channel of the Platte River/Turkey Creek had eroded to within 5 feet of a local sandpit. The U.S. Corps of Engineers surveyed the problem and provided an Emergency 404 permit to the NRD to stabilize the bank. The City of Kearney provided 25% of the total cost (approximately $1,850) and the NRD provided $13,500.
Kirkpatrick Memorial Park Lake In October 2016, the board approved a $25,000 request from JEO towards lake improvements for the Kirkpatrick Memorial Park Lake in Lexington, NE. Improvements include 4,000 cubic yards of dredging, 2,500’ of bank improvements including removal of trees, and a 700’ seawall to the four-acre lake. The project will provide improvements to water quality, aquatic habitat, public access and provide an area for educational events. Construction is expected to be completed in the fall of 2017.
Lake Helen In 2013 & 2014, CPNRD provided $75,000 towards the restoration of Lake Helen in Gothenburg for water quality conditions. The lake was drained to accommodate: excavation of 171,773 cubic yards of sediment, stabilization of 3,391 linear feet of shoreline, development of underwater shoals, installation of a circulation system, dam repair, installation of a pier and boat ramp. Sediment and nutrient loading from outside the lake boundary was addressed by treating the lake with aluminum sulfate to precipitate phosphorus, installing a deeper well to access lower phosphorus water, and stocking recreational fish. The total cost of the water quality and habitat project was nearly $1.8 million. The project was completed in 2016.
Lepin Ditch Flood Control Project Landowners petitioned CPNRD in 1993 to solve excess storm runoff that was overloading the “old north channel” of the Platte River north of I-80 in southwest Hall County. A study by Nebraska Department of Roads (NDOR) & CPNRD determined that the problem resulted when I-80 was constructed and an attempt was made to redirect runoff from the Lepin Ditch to another crossing site under the Interstate. This joint project was developed to place a culvert in the vicinity of the natural channel to allow runoff to flow under the Interstate at $700,000 with partners CPNRD, NDOR and Hall County. Easements were obtained from area land-owners for construction and maintenance of the ditch. The county provided site preparation and ditch excavation and provides maintenance. CPNRD contributed $120,000; which was completed in 1995. NDOR provided funds for the culvert.
Moores Creek Flood Control Project In the 1980s, CPNRD, and others recognized the need for flood control in Hall & Merrick counties on Moores Creek. Project sponsors- CPNRD, City of Grand Island, Merrick & Hall counties– submitted the feasibility study to the Nebraska Natural Resources Commission in January 1984. The Commission approved the Moores Creek Project and agreed to cost share at a 65% rate. A three-phase construction plan was developed and carried out. Phase I: Channel improvements from the mouth near Archer upstream to the Hall-Merrick county line were completed in 1990. Phase II: Three detention/retention and wildlife habitat enhancement cells were completed on Moores Creek channel from the Hall-Merrick county line upstream to Grand Island. Phase III: Waterways and bridges were constructed to enable storm runoff from the Capital Heights area, northwest of Grand Island, to drain into the improved Moores Creek channel. Project was completed in 1995. Annual maintenance is completed as needed with an approximate cost of $20,000.The U.S. Army Corps of Engineers participated in studies in the early stages of the Project. Following new rules for such projects adopted in the 1980s, the Corps reviewed its findings and conducted reconnaissance studies to determine if a project was possible after the criteria changed. The review indicated highly feasible floodway projects using several different routes. Following public hearings in 1989, the Corps narrowed the choices and began a study to determine the actual feasibility of a route to carry excess water from the Wood River and Warm Slough into the Platte River. Appropriation and construction-start authorizations were obtained from Congress in 1996. The Corps’ revision of plans and increased projected cost required new Congressional re-authorization, accomplished in 1999. Construction began in March of 2000. In 2002, the Corps contract was increased by $1 million due to miscalculations regarding the amount of topsoil needed for the project. 180,000 yards of soil was added with co-sponsors paying $95,000 of the increase.
A total of 500 acres were involved in land acquisition for the project; 2 miles west of Hwy 281 to the Hwy 34 bridge along the Platte River where 5 bridges were constructed. A reappraisal of Hall County Park resulted in an agreement/compensation for damages to the RV park with the Hall County Board. The board proceeded with the remaining 11 tracks of land needed for the project. Benefits of the project include flood control for flood zones in the Grand Island, rural Hall and Merrick counties and groundwater quality improvement. Close to 7,000 acres of land were taken out of the flood zones. FEMA revised its floodplain maps in 2004, taking away the need for flood insurance in southern Grand Island. Landowners had been paying $317,000 to protect $56 million worth of property prior to the revision of the floodplain maps. Full funding of the Federal share enabled construction to be completed on schedule. CPNRD borrowed funds in the amount of $1.1M at an interest rate of 6.5%, to meet the needs of project construction over a 2-3 year period. All monies were reimbursed to CPNRD by the State of Nebraska through a cost-share grant and the other local sponsors. The entire project was completed and dedicated in May 2004. Total cost was about $15 million as follows: $7,148,000- U.S. Army Corps of Engineers, $4M– Nebraska Department of Natural Resources, $1.4M- CPNRD, $1.2M-City of Grand Island, $352,000- Hall County, $200,000-Merrick County. CPNRD is responsible for maintenance, with costs split between the cosponsors. In 2015, $25,000 was approved for JEO to complete design work for the Wood River Flood Control Project’s System-Wide Improvement Framework. The board also approved $20,000 for maintenance and repairs required by the Corps of Engineers.
Odessa Area Flood Control Project Miller & Associates of Kearney started the final design of the Odessa Area FCP in 2008 and completed it in 2010 at a cost of $15,000. The Project is located east and south of the project boundaries include the Odessa Road to the west, 24 Road to the North, and Sartoria Road to the east. The 2-mile project consists of improvements to existing roadside and field drainage ditches, replacement of culverts and supplementing existing culverts.
Platte County Project The Platte County Project is an improvement area located just southwest of Duncan. The project provides drainage improvement and minor flood control benefits to 1,300 acres of irrigated cropland in southwest Platte County. Maintenance is performed as necessary at an estimated cost of $500-$1,000 annually. Actual costs are calculated and assessed to benefiting landowners.
Prairie Creek Clearing Project Flooding from Prairie Creek caused considerable damage to agricultural property in the past. While the Prairie-Silver Creek Flood Control Project had a local effect, it didn’t solve all of the flooding problems on Prairie Creek, nor did it evolve that a feasible project could be developed to solve all of the flooding problems on the stream. Further study indicated that damages could be reduced by keeping the channel clear. Snagging and clearing projects involving the selective removal of timber, trash, and debris from the stream channel in an area of 35 feet on either side of the center of the channel were completed from the mouth of Prairie Creek in Merrick County to the Hall-Buffalo county line. Annual maintenance is approximately $10,500.
Prairie-Silver Flood Control Project A flooding problem was studied by the NRD in central Hall County, just west of the city of Grand Island. CPNRD determined that the problem was caused by two short stretches of Prairie Creek and Silver Creek that produced channel overflow after large storm events. A project was developed to correct the problem by cleaning out the channels and constructing training levees to prevent the Construction was completed on the project in 1986. Construction and land leveling in the area disturbed natural drainage flows along the Prairie/Silver Creek, northwest of Grand Island. In 2000, a design proposed by the NRCS was approved by the board to install a uniform drain and add culverts for a two-mile stretch. The total cost was $22,000 of which the NRD provided $17,500.
Silver Creek Watershed Located in Merrick County, this watershed encompasses approximately 90,000 acres. A feasibility study was completed in 1979 to provide flood relief in the watershed with the project completed in four parts that consisted of mainly channel improvement. Phase 1A: Lower 4.1 miles of Silver Creek. 1B: One mile of Silver Creek and 15 miles of the Clarks drain. Phase 2: Continued upstream on Silver Creek for 6 miles. Phase 3: The next 10 miles upstream. Phase 4: Wasn’t completed until the fall of 1987 due to wet weather in the 1985 & 1986 construction seasons. The 11-mile stretch upstream from Hwy 14 north of Central City to Silver Creek’s headwaters west of Chapman. The Board approved the extension of the project at a cost of $7,500 in February 2000 due to additional flooding. Maintenance costs are approximately $20,000 annually.
Warm Slough/Trouble Creek Flood Control Project Due to a history of flood damage to agricultural and urban property within Central City, a project was proposed for reducing flooding along those streams; caused by storm runoff into the Warm Slough, Dry Run, and Trouble creeks. That project would have included construction near Grand Island in order to take care of storm runoff from the city, as well as channel clearing and renovation from Grand Island to Central City. A study determined that portions of the project were not economically feasible. A revision was made that subsequently dropped the infeasible portions of the plans. Partial funding was provided by the state through the NE Natural Resources Development Fund. Cosponsors, with varying shares of the local matching portion, were CPNRD, Merrick and Hall counties, and cities of Grand Island and Central City. Construction was completed in 1993 and maintenance responsibilities were turned over to Merrick County and Central City. In 2002, the NRD performed snagging and clearing of the Lower Warm Slough from Grand Island to Central City with an initial cost of $110,000. Additional funds in the amount of $23,000 were transferred to complete the project since the construction company was required to truck the dirt away due to the close proximity of wetlands in the area. From June 1-8, 2008, Central City received over 6” of rainfall, which exceeded a 100-year event. The project has improved drainage of the entire watershed.
Wood River Watershed In 1972, snagging and clearing was completed from the mouth of the stream to Gibbon in 1972. In 2002, one mile was cleared at a cost of $20,000. Annual maintenance for the Wood River Clearing Project is about $10,000. Additional spot clearing is completed as needed.
Wood River Flood Control Project The Wood River has 173 miles of channel meandering through the Platte River Valley with numerous flood control structure sites in its upper reaches. During the June 1967 flood on the Wood River, most of the rain fell east of Kearney where there were few flood control structures sites. 10’ of rain fell over 9 days from June 7-15, with 3.2” falling on June 13. Extensive damage was done in Grand Island. Following new rules for projects adopted in 1980s, the U.S. Corps of Engineers conducted reconnaissance studies and found highly feasible floodway projects using several different routes. Following public hearings in 1989, the Corps began a study to determine the actual feasibility of a route to carry excess water from the Wood River & Warm Slough into the Platte River. Appropriation/construction to start authorizations were obtained from Congress in 1996. The Corps’ revision of plans and increased project costs required new Congressional reauthorization in 1999. Construction began in March 2000. In 2002, the contract was increased by $1M due to miscalculations regarding the amount of topsoil needed with 180,000 yds of soil added with co-sponsors paying $95,000 of the increase. 500 acres were involved in land acquisition for the project; 2 miles west of Hwy 281 to Hwy 34 bridge. Reappraisal of Hall County’s RV Park resulted in compensation for damages to the Hall County Board. The board proceeded with the remaining 11 tracks of land needed for the project. In 2005, a total of 7.21” of rain fell between May 11-12, more than any one-day of rainfall during the 1967 Flood. The 300’-wide channel provided flood protection for 1,500 homes/businesses. On June 1-8, the project was tested again with 6” of rain. Benefits of include flood control for Grand Island, rural Hall/ Merrick counties, & groundwater quality improvement. CPNRD borrowed $1.1M for construction over 3 years. CPNRD was reimbursed by the State of Nebraska through a cost-share grant and local sponsors. The entire project was completed and dedicated in May 2004.
A Reduced Risk of Flooding According to the USACE National Levee Database, the Left Bank Levee System provides flood risk reduction for 15,514 acres of land ranging from farmland to developed residential, commercial, and industrial land uses. This includes approximately 9,360 people and 3,919 buildings, of which 3,655 are residential. The Right Bank Levee System provides flood risk reduction for an additional 1,337 acres of land consisting of mostly farmland. This includes approximately 120 people and 45 structures, of which 39 are residential. FEMA’s revision of floodplain maps removed close to 7,000 acres of land out of the flood zones and the need for flood insurance in southern Grand Island. CPNRD is responsible for operating and maintaining the levee system to federal standards. Total cost $15M as follows: $7,148,000-Corps of Engineers, $4M–NeDNR, $1.4M-CPNRD, $1.2M-Grand Island, $352,000-Hall Co. and $200,000-Merrick Co. CPNRD is responsible for maintenance, with costs split between cosponsors. In 2015, JEO was hired for $25,000 to complete design work for the Project’s System-Wide Improvement Framework. $20,000 for maintenance/repairs is required by the Corps of Engineers. While the levee system significantly reduces flood risk, it cannot eliminate it. There are several things YOU can do to manage the “residual flood risk,” or the risk that the levee system cannot eliminate:
Know Your Risk: Use the National Levee Database and the Federal Emergency Management Agency’s Map Service Center to determine your flood risk.
Consider Buying Flood Insurance: Buying flood insurance helps ensure that your home and belongings are insured in case of damages from flooding.
Create an Emergency Preparedness Kit: Create an emergency preparedness kit for you and your family for when severe weather and flooding occur and take time to make an evacuation plan.
Upper Prairie/Silver/Moores Flood Control Project CPNRD and the City of Grand Island completed a detailed hydrology analysis and 100-year floodplain in the upper parts of the Dry, Prairie, Silver & Moores Creek watershed, located south of Hwy 2 & east of Hwy 281. Upland and lowland flood control structures were developed with roadways to act as dams, berms built to keep creeks within their banks, and water detention cells built on 500 ac. at the former Cornhusker Army Ammunition Plant. $8.3M in cost-share funds was provided by the Nebraska Natural Resources Commission for the 10-year, $15.5M construction project. The remaining $7.2M was financed by co-sponsors.
The project protects northwestern Grand Island from Prairie & Silver Creek flooding; reduces future flood damages to crops, properties, and infrastructures; and eliminates an estimated $130M in damages during a 100-year event. Construction included: 3 floodwater retarding sites in upland areas of Prairie Creek watershed southwest of Cairo; 1 upland detention site in Dry Creek watershed; a series of small detention sites in lowland areas along upper Prairie Creek; 3 excavated off-channel detention sites in Silver Creek Watershed; 1 low-level berm to prevent basin overflows from Silver Creek into Moores Creek; clearing to improve capacity.
Construction was phased over 10-years, starting with the off-channel lowland sites in Silver Creek. The study showed that a 100-year flood would inundate 23,000 acres south of Hwy 2, producing crop damages of $3M/10-year flood $1.6M. Flood waters would collect along Hwy 2 resulting in large quantities of water flowing east into developed areas of northwest/west Grand Island. On May 11, 2005, Grand Island sustained $3-5M in flooding damages & Hall County $12-15M. Nearly 3,000 homes/businesses that were damaged would’ve received flood relief from the project. Acquisition of easements included 1,800 acres, excavation of 3,500 AF of off-channel storage in lowland areas, construction of 6 upland floodwater detention dams/outlet works, and installation or replacement of roadway culverts under Hwy 2 & county roads. 500 acres of irrigated cropland were acquired for detention cells. Construction began in 2006. In 2011, a revised agreement with Hall County on White Cloud Rd dam to install a maintenance fund of $10,000 for 10 years for erosion, gravel, etc. In 2015, JEO was hired for $118,650 to submit a Conditional Letter of Map Revision (CLOMR) to FEMA providing an assessment of the flood risk reductions due to flood control measures. In 2016, 7.25 acres of irrigated land was condemned at Engleman/Airport roads following unsuccessful negotiation attempts. The property is central to the existing levy and to a new levy.
Phase I, the north detention cell on Airport Road was completed in 2016. Equipment included 4 scrapers that held 20 cubic yards, 2 excavators, 4 dump trucks held 30 cu/yds, bulldozer, & road grader. 71,500 cu/yds was excavated to form the north cell. The southern portion of Phase I included 815,000 cu/yds & is located at Capital/Schauppsville roads. Seeding/mulching for erosion control will take place as needed. Hooker Brothers constructed the Phase II detention cell for $2.2M; $1.18M below estimate. 1 million cu/yds of dirt were excavated. Construction on 4 upstream dams & detention cells were completed in 2017. Levee construction at the intersection of Airport and Engleman roads was completed in 2019.
In August 2018, FEMA approved the Conditional Letter of Map Revision (CLOMR), including floodplain maps for northwest Grand Island/portions of Hall County. The CLOMR approval is essential to provide assurance that FEMA will accept the technical information necessary to update the floodplain maps when the Letter Of Map Revision is submitted. Click here for Q&As to frequently asked questions regarding the LOMR & floodplain mapping.
For more information on CPNRD’s flood control projects, contact Jesse Mintken.