Chena Project Office Phone: 907-488-2748/6349/6509

Facebook: http://www.facebook.com/AlaskaCorps

In addition, the Fairbanks North Star Borough provides frequent updates at:

• Public Information Line: 907-459-1213
• Department of Emergency Operations: http://www.co.fairbanks.ak.us/EmergencyOperations/default.htm
• "Icecast" internet webcasting service: https:www.co.fairbanks.ak.us/fnsbwebcast/fnsbwebcast.htm
• Facebook: https://www.facebook.com/FNSBGov

The Fairbanks North Star Borough’s Department of Emergency Operations offers detailed information about flood preparation and safety. 

To check out these resources, call the borough information line at 907-459-1213 or go to: http://www.co.fairbanks.ak.us/EmergencyOperations/default.htm.

The Fairbanks North Star Borough is responsible for coordinating emergency response activities in areas impacted by severe flooding. Services include the distribution of sand and sandbags as well as potable water.

For details, call the borough information line at 907-459-1213 or visit the webpage for its Department of Emergency Operations at: http://www.co.fairbanks.ak.us/EmergencyOperations/default.htm

Hazards are always a concern during flood season.  The Corps recommends that people review current flood warnings and stream conditions before recreating along the river.  This information is available at:

•  Chena Project Office phone lines: 907-488-2748 / 6359 / 6509
•  Chena Project webpage: http://www.poa.usace.army.mil/Locations/ChenaProject.aspx
•  Facebook: https://www.facebook.com/AlaskaCorps

This facility is operated by the Fairbanks North Star Borough’s Department of Parks and Recreation. Inquiries about the status of the park should be directed to 907-488-1655 or http://www.chenalake.com/.

When the stream flow through the dam reaches 5,000 cfs, wood and other debris is mobilized upstream of the dam and creates a hazard to boaters. In response, we lower "trash racks" into the river to trap the floating debris and use a crane to remove it from the river. These contracted bailing operations are necessary to prevent water flow and boat traffic from being impeded.

The Corps will issue public notices to advise boaters on whether it is safe to pass through the dam control works. In addition, signage and flashing lights near the dam will warn boater traffic if the corridor is not clear of debris or if a flood control operation is underway.

In the process of monitoring stream flow and flood conditions, Corps employees may request access to private property to survey and photograph areas along the Chena River.

Upon arrival at a site, our protocol is to ask for permission from the landowner before proceeding.  Corps personnel can be identified by their attire bearing the red and white castle logo.  In addition, they can provide printed materials with Corps contact information and details about how to obtain status updates.

Members of the public are encouraged to submit reports, photos and videos that document changes in water elevation and conditions to Public.Affairs3@usace.army.mil.

If the dam gates have not been lowered, we have not begun flood operations. Most likely, this is a local drainage problem that should be brought to the attention of the Fairbanks North Star Borough’s Department of Public Works at:  http://www.co.fairbanks.ak.us/PWorks/Default.htm.

As of the last flood control operation in June 2020, the total damages reduced by the project are estimated at $418 million.

Since Moose Creek Dam began operations in 1979, the Corps has successfully managed 30 flood events with the last in June 2020.

Corps of Engineers hydrologists at the Alaska District Headquarters in Anchorage continually watch weather systems that traverse the area. An automated set of climatological stations throughout the Chena watershed provide information for the use of hydrologic models to forecast stream flow conditions at various points along the river. When flood conditions are predicted, the Chena Project staff are alerted and a standard set of operational procedures are followed. Upon the arrival of high water at the dam, gate settings are called in to the dam tender by the District hydrologist.  Chena dam tenders then adjust the gate openings per instructions. The Chena staff and the hydrologists work together communicating steam flow and impoundment information around the clock whenever the project is in a flood posture.

Typically, rainfall events have a short duration characterized by a rapid rise to peak flow followed by a rapid fall back to normal flow levels.  Snow melt events have a longer duration with a gradual buildup to peak flow followed by a more rapid drop to normal flow. 

Major floods in the basin result from rainfall or a combination of rainfall and snowmelt. When rain augments snowmelt runoff, the floods have both high peaks and large runoff volumes.  This is especially true when the ground is frozen.  Flood peaks from rainfall are generally of a short duration, but can be exceptionally high, which was the case during the 1967 flood of record.  Peaks from a combination rainfall and snowmelt are of a longer duration.

The Corps monitors the basins which feed the Chena River in order to predict the occurrence and severity of flood events. Remote climatological stations for measuring precipitation, snow water equivalent and air temperature are located at selected sites within the basin and provide early warning of potential high water conditions.

Six sites are presently in existence and cooperatively maintained by the U.S. Army Corps of Engineers and the Natural Resources Conservation Service.  Data from these sites are telemetered to the Hydraulics and Hydrology Section at the Alaska District Office in Anchorage for evaluation and use in flood control forecasting.  Failure in this portion of the hydroclimatological system will decrease the warning time for a high water event, and limit the accuracy of flood forecasts. All of these sites are helicopter accessible.

There are five road accessible hydrologic gauging stations associated with the Chena project. These sites provide the following information:

• Chena River near Two Rivers: provides discharge information for the Chena River. Located about 25 air miles upstream of the control works.
• Chena River near Hunts Creek: provides discharge information approximately 12 air miles upstream of the project.
• Chena River near North Pole: provides information for the combined discharges of the outlet structure and the seepage channels just downstream of the outlet works.
• Little Chena River near Fairbanks: provides discharge information on the Little Chena River, the primary source of local inflow between the control works on the Chena River and the City of Fairbanks.
• Chena River in downtown Fairbanks: provides discharge information approximately 16 air miles downstream of the project to ensure regulations are mitigating flood risk for Fairbanks as Congressionally manadated.
• Chena River near the Tanana: provides discharge information near the confluence of the Chena and Tanana Rivers near Rosie Creek subdivision and allows identification of possible backwater effects from Tanana River high flows. 

The combined information from the North Pole gauge and the Little Chena guage are an excellent indicator of the subsequent flows headed downstream to Fairbanks. 

For discharge information, the USGS publishes stream gauge data at: https://dashboard.waterdata.usgs.gov/app/nwd/en/.

For flood watches or warnings, check the National Weather Service forecast for Fairbanks available through: noaa.gov.

The most significant event in the Chena Project's history occurred in 1992 when the dam impounded water to 512.7 feet (NAVD88), which is about 19 percent of its capacity. This is the only occurrence when water spilled over the control sill and flowed into the Tanana River. The dam gates were closed from May 25 to June 11. During this period, the peak flow from the dam measured 8,200 cfs, while the peak flow in Fairbanks reached 10,500 cfs.

Typically, the gates are closed when the discharge rate through the dam reaches about 8,200 cfs. However, the trigger point to lower the gates is based on an assessment of conditions on the Chena upstream of the project, the conditions on the Little Chena, and conditions on the Tanana. The project will be operated in order to keep flows in Fairbanks from exceeding bankful (~12,000 cfs) but that operation may be different based on ice jam conditions and rainfall concentration across the basin.

When the discharge rate through the dam is around 8,600 cfs, downstream areas (Steamboat and Freeman Road), historically experience flooding. Therefore, increased monitoring and surveillance of these low-lying areas is required.

Public Law 90-483 of the 90th Congress (S-3710) authorized the Chena River Lakes Flood Control Project on August 13, 1968. It established a flood regulation objective of 12,000 cubic feet per second (cfs) through downtown Fairbanks and ensuring that the discharge was well within the channel capacity of the Chena River at Fairbanks.

The 1988 Environmental Assessment (EA) originated from public concerns that date back to the 1983 to 1985 time period where it was believed that the 12,000 cfs maximum release in downtown Fairbanks may be too high.  High water events in 1983 and in 1985 caused flooding of driveways and basements in the Steamboat Landing area and ground water problems were reported in the Laurance, Nelson and Lyle Road areas below the Dam.  The outcome of the EA hinged upon results from the Fairbanks Flood Insurance Study (FIS) that was going on at the time for the Federal Emergency Management Agency.

The FIS determined water surface elevations of various flow rates along the Chena River from Moose Creek Dam downstream to its confluence with the Tanana River.  The study found that a flow of 12,000 cfs was within the confines of the Chena River in downtown Fairbanks. 

The 1988 EA was finalized when former District Engineer, Colonel William W. Kakel signed the Finding of No Significant Impact on July 19, 1988.  This finding has not been amended or changed.

The only formal document necessary to finalize an Environmental Assessment is a signed "Finding of No Significant Impact" (FONSI).  This document was mailed out in September 1988 to all who received copies of the draft EA.  Among those who received copies are residents of the Steamboat Landing area, the Fairbanks North Star Borough, the US Fish and Wildlife Service, Alaska Department of Fish and Game, along with a number of Corps offices.  Additional copies are available from the Environmental Resources Section in the Corps of Engineers, Alaska District.

The floodplain development downstream of the dam and the subsequent loss of floodwater conveyance increase the length of time water is held behind the dam because of reduced outflows. These reduced outflows increase the length of time that water is impounded in the floodway and consequently raises ground water levels in the North Pole area. To address this dilemma, the Corps has made surface water flood reduction a priority over ground water flood reduction. The reason for this is that surface water flooding can occur more rapidly and offers a greater potential for the loss of life. Flooding from ground water infiltration involves a lag time where preventative measures can be taken to remove valuables from crawl spaces and basements. The Moose Creek Dam was not designed to prevent ground water flooding, as it is situated on top of permeable soils that in some places are over 600 feet deep. This means that when the flows on the Little Chena River necessitate reductions in outflows to a minimum to keep downtown Fairbanks flows from exceeding 12,000 cfs there will be substantially more ground water problems downstream of the dam than we have seen to date. 

In response to anticipated ground water flooding potential in the North Pole area, the Fairbanks North Star Borough prohibits construction of finished living space below grade in new homes within one mile below the Moose Creek Dam.  This ground water zone was derived as a result of a ground water flow modeling effort performed by the Corps Hydrologic Engineering Center in 1995.  Reference can be made to U. S. Army Corps of Engineers, The Development and Application of Initial Hydrogeologic Flow Model for the Chena River Lakes Flood Control Project, July 1995, for more details.

The project was designed to limit stream flows on the Chena River to no more than 12,000 cubic feet per second (cfs) at the gauging station in downtown Fairbanks.  Reaching this level depends on many hydrologic factors and is not a required level to reach every time there is a gate closure at the dam.  The primary concern to the Corps during a flood event is what the unregulated Little Chena River and other drainages located between downtown Fairbanks and Moose Creek Dam are contributing to the total discharge.  The Little Chena River alone has an expected 100-year flood potential in excess of 11,000 cfs which means to keep flows under 12,000 cfs in downtown Fairbanks, the Corps must regulate flows at the dam at the minimum flow of 1,000 cfs.  Under the same scenario, it is very likely that a large event will also occur on the Chena River requiring substantially more water to be diverted into the floodway than occurred during June of 1992 flood of record. This translates to a longer duration of flow over the sill, and hence more severe impacts to the ground water table below the dam than anyone has seen to date.

Past operations of the dam have allowed flows in downtown Fairbanks to exceed 11,000 cfs but only because of the contribution from the Little Chena River and other drainages below the dam.  In June 1992, flows at Fairbanks reached 10,500 cfs.  The dam was designed to release a total of 10,000 cfs from the control works (including the seepage collector channels) but since coming on line in 1979, the Corps has never released more than 8,700 cfs.  This is due to the residential development and road improvements (including increasing heights) that have occurred in the Steamboat Landing/Dehmer area since the project was originally authorized.  In June of 1992, releases from the dam were held to 8,000 cfs because of complaints of flooded  riveways and water in various residences in the Steamboat Landing/Dehmer area.  In July of 2003 Freeman Road was resurfaced thereby adding additional height to which waters must reach before overtopping and thereby increasing flood potential on its upstream side. 

This is one of the Corps’ main objectives in operating the dam.  It is restricted, however, during certain periods when upstream-migrating fish must use the fish ladder that requires a pool be established to an elevation of 502 feet (MSL).  This requirement prolongs the length of time water is impounded, but is a requirement set forth by the Alaska Department of Fish and Game.

Other than this, it has always been the Corps' objective to operate the project in such a manner where water is retained and diverted for the shortest period of time possible provided flows in downtown Fairbanks don’t exceed 12,000 cfs.  It not only minimizes human and environmental impacts but also reduces operating costs through less maintenance and staff overtime.

Our desire is to release the 10,000 cfs design capacity of the outlet works, but we have been unable to for the reasons stated in the answer to question #4 above.

The original authorization of the project included a provision for the Government to purchase real estate that would be flooded, but only for properties upstream of the dam that existed at the time. 

The project was designed and authorized before the Steamboat Landing area was developed and few people were living in the area. 

The 1973 Local Cooperation Agreement made a provision for the Fairbanks North Star borough to "prescribe and enforce regulations to prevent encroachment on downstream channel capacities for regulation of the reservoir."  To purchase the property now would require a new authorization from Congress to do so.

The Fairbanks North Star Borough has known about the ground water impacts from water being impounded behind the dam since the conceptual design of the dam was completed.  The project is underlain by some 600 feet of gravel, as are other areas around the Borough.  A letter from Mr. Harry Cedergren to the Alaska District in 1974 said that an area approximately one-half of a mile downstream from the dam could expect ground water problems during an impoundment period.  This letter is contained in Design Memorandum (DM) 10, Volume 2 of 2 dated May 28, 1974.  This DM along with the others for the project has existed here in the District, the Chena Project Office, and the Fairbanks North Star Borough since its completion in 1974.

Other subsequent correspondence exists that discusses the ground water problems below the dam.  There is a letter dated June 18, 1985 from Acting District Engineer Lt. Col. Roy Carlson to Borough Mayor R. B. Allen that discusses the ground water problems.  An article in the September 22, 1977 edition of the Fairbanks News-Miner cautioned against development in the flood prone areas downstream of the Moose Creek Dam.  Another article appeared eight years later in a May 1985 edition of the Fairbanks News-Miner warning citizens about dangers of construction in the flood plain.  Borough Mayor Juanita Helms wrote to Senator Frank Murkowski on November 8, 1985 regarding the impacts of Chena River flooding.  Additional information can be found in Corps files.

The only documentation that still exists is contained in the set of Design Memorandums on file in the Alaska District, the Chena Project Office, and the Fairbanks North Star Borough.  The actual letters from the Corps to the Fairbanks North Star Borough transmitting these documents and requesting their review have been retired and destroyed because of their age. 

Following the June 1992 high water event, Congress appropriated funding for a ground water flow modeling study.  This work was performed by the Corps Hydrologic Engineering Center in Davis CA and was completed in 1995.  It became the basis for which the Fairbanks North Star Borough established additional land use restrictions within a one-mile area below the Moose Creek Dam.  Reference can be made to U. S. Army Corps of Engineers, The Development and Application of Initial Hydrogeologic Flow Model for the Chena River Lakes Flood Control Project, July 1995, for more details.

In conjunction with the ground water modeling study, Congress also appropriated funding for a separate study to evaluate the ground water effects below Moose Creek Dam and determine if operational changes could be made to mitigate the problem.  This study was in direct response to the largest impoundment to date that occurred in June of 1992.  Results of this study can be found in the U.S. Army Corps of Engineers, Ground Water Effects Below Moose Creek Dam, Letter Report No. 25, July 1996.  Copies of this report are available at the Chena Project Office and are also on file at the Alaska District and Fairbanks North Star Borough offices.

Letter Report No. 25 investigated a number of potential options to alleviate ground water problems in the affected area. Lining the floodway with an impervious membrane, constructing a cut-off wall down to bedrock, lowering the Tanana sill, or constructing an aqueduct could greatly reduce seepage under the dam.  Installing a series of pumped wells between the dam and the areas most affected by the ground water problems could lower the ground water during the flood events to a level where basement crawl spaces, septic systems, and wells are not affected.  Floodproofing of individual structures may also reduce damages.  Unfortunately, none of the above potential solutions were found to be economically feasible.

The study also found that operational measures to reduce pool elevations impoundment durations behind the dam would only slightly reduce the frequency of the ground water problems.  The range in size of events where this option would have any effect is so small that the benefits would be negligible to the residents of North Pole.  Furthermore, to be effective, dikes would have to be constructed in areas that are currently outside of the project boundary and authorization.

With no economically feasible structural solutions available, the Corps plan of action is to continue project operations as has ben done in the past and increase public awareness of the ground water flooding problem using the news media and recurring meetings with the Fairbanks North Star Borough.

A Flood Insurance Study (FIS) is a study initiated and funded by the Federal Emergency Management Agency to determine flooding levels in a community for the purposes of establishing an actuarial insurance rating system.  Flood insurance is made available to communities who agree to enforce land development through local ordinances and are willing to meet other Flood Insurance Program requirements.  The program was originally set up to avoid the large costs of providing disaster assistance after a major flood.  Qualified engineering firms as well as the Corps of Engineers who contract with FEMA perform the studies on an as needed basis. 

For further information, we recommend that you contact the FEMA, Region 10, Federal Regional Center, Bothell WA 98011.

The agency’s guide to floodplain management and the National Flood Insurance Program is available at: http://www.fema.gov/media-library/assets/documents/15477?id=3574

Yes, there are and they are available from FEMA.  Sets of these maps are available for inspection in at the Fairbanks North Star Borough, Planning Department and Corps Alaska District office in Anchorage.

There are a number of currently unpopulated areas along the Chena River that are affected by our flow releases besides the Steamboat Landing area.  The Corps tries to encourage everyone not familiar with these maps to get acquainted with them so more flood awareness problems don't come as a surprise in the future.

There are probably lots of reasons for this, which would best be answered by FEMA; however, we do know that it would be extremely expensive to undertake such an effort.  Disaster relief, along with ground water flooding insurance would be weighed by FEMA against the cost of other alternatives.  One of these is land use restriction.  This option may well be less expensive and more practical than insurance payments.  Land use restrictions are, however, opposed by many residents as overly burdensome to their property rights.