Flooding Update


May 12, 2017


The majority of the Greenbelt bike and pedestrian path remains closed due to dangerous flood conditions on the Boise River. This closure will remain in place until flows decrease and sections are deemed safe to use.

All but approximately 11 miles of Greenbelt pathway through Ada County will be closed due to the river conditions

  • Current Boise River flows exceed 8,000 cubic feet per second with the high, swift and cold water making conditions extremely dangerous – potentially fatal -- for people and pets. Because of this winter’s deep snow pack, these conditions are expected to remain into June, at least.

  • The Greenbelt closure restricts access to all low-lying areas of the Greenbelt vulnerable to the flood waters. (see county-wide map

  • The closure will remain in effect until the dangerous river conditions subside. Several sections of the Greenbelt, totaling approximately 11 miles of pathway, are expected to remain unaffected by the flooding and will remain open. This includes the section managed by the Ada County Parks and Waterways Department between Warm Springs Golf Course and Lucky Peak Dam. 
    • All bridges remain open
    • The Greenbelt from Shoreline Park at the Idaho Fallen Firefighter Memorial is open so commuters can travel up and over the Trestle Bridge and continue on to N. Orchard Street
    • Baggley Park and sidewalks that the City of Boise maintains remain open


  • Stay up to date: https://adacounty.id.gov/accem/Flood-Information
  • Stay away from the river. Do not recreate in the river, as very cold swift water is life threatening.
  • Keep pets leashed and away from the river, they may chase other animals/wildlife into the swift water.
  • Portions of the Greenbelt have detours or closures posted due to high water. Keep updated on the latest Greenbelt information.
  • If someone gets into trouble in the river, call 9-1-1 immediately. The 9-1-1 Dispatcher needs to know how many people are in the water and where they are located; (closest street, bridge crossing, park, side of the river, Greenbelt Mile Marker etc.)
  • The city may impose a charge to recover costs incurred for responding to a rescue on the river. (More information below.)


  1. Why is the Boise River flooding? A number of factors impact the level of flow of the Boise River.  The primary reason that the river in town is at flood stage is the need to release water from reservoirs that are being filled with snow melt.  The Bureau of Reclamation and the US Corps of Engineers jointly manage the dams for both irrigation supply and flood control, and have to balance reservoir capacity with river flows.  Weather also has an impact on these decisions.

  2. Who decides how much water to release from the dams? Dam operators with the U.S. Army Corps of Engineers and Bureau of Reclamation work cooperatively with the National Weather Service and the Natural Resources Conservation Service to assess and plan for the amount of water expected to flow into the reservoirs in short term and long term. Based on their assessments, they determine how much water will flow into the Boise River to ensure that the reservoirs and dams keep enough safe capacity.  Dam mangers try and balance near term high river flows, to decrease the risk of even higher river flows later.

  3. Is the flooding going to get worse? While we cannot fully predict whether flooding will get worse, public safety is the first priority, and we ask that residents stay up to date on flood conditions, and consider signing up to receive emergency alerts through the Ada County Emergency Management website: https://adacounty.id.gov/accem/Flood-Information.    The amount and severity of flooding is dependent on a number of factors, primarily the weather, reservoir capacity, and how fast the mountain snowpack melts. 

  4. Why has a “Dangerous River Condition” been posted for the Boise River? Boise Fire Department has posted the “Dangerous River Condition” for the Boise River for the following reasons:

- Swift water can carry people & pets away rapidly.
- Cold water can cause even the best swimmer to be incapable of swimming due to loss of motor control/muscle control.
- Significant debris in the river can injure people and contributes to rescue equipment failure.
- Flooding conditions make access to river more dangerous if not impossible.
- Water has approached bridge height making passing under a bridge extremely dangerous or not possible.

  1. How long will flooding last? Based on best estimates, we expect the river to be at above average flows through June.
  1. How do I know if my property will get flooded? While there are no certainties on which properties will flood or not, FEMA produces flood maps to guide which properties need flood insurance and these maps provide some guidance as to which areas are at risk.  More information on flood maps and flood insurance can be found here:  https://adacounty.id.gov/accem/Flood-Information
  1. Who is taking the overall lead on preparation and flood response? A county-wide incident management team has been set up to coordinate flood monitoring and response.  More information on Ada County Emergency Management can be found here https://adacounty.id.gov/accem.
  1. Who do I call to report flooding?
    1. Emergencies: Call 9-1-1
    2. Flooding within Boise from the river or foothills gulches: Boise Public Works Department
      1. 208-608-7150 during business hours
      2. 208-384-4262 evenings and weekends
    3. Flooding in the roadways or public storm drains: Ada County Highway District
      1. 208-387-6100 during business hours
      2. 208-377-6790 evenings and weekends
  1. Are sandbags being supplied? The City of Boise is not currently issuing sandbags.  If river flooding elevates to the point where property is threatened, The City of Boise will issue sandbags to residents (up to 25 per property).  More information on sandbags can be found at https://adacounty.id.gov/accem/Flood-Information.
  1. Is there risk to the West Boise Wastewater Treatment Facility? A problem has been identified with a privately-owned gravel pit that sits next to the Boise River near Eagle Island and just east of the Island Woods/Two Rivers neighborhood.  If the ground around the pit fails, which engineers expect to happen, it is likely to have limited impact on the treatment facility, with the primary impact likely being access to and from the facility by potentially flooded roads.  The treatment facility, and its critical infrastructure sit on higher ground, above even a 100-year flood event.  A coordinated team continues to monitor the situation, and has taken precautionary measures.
  1. Where can I get more information? Additional information can be found on the Ada County Emergency Management page: https://adacounty.id.gov/accem/Flood-Information


  1. Which sections of the Greenbelt are closed? Please view the updated map for the most recent Greenbelt closures. Also available is our Boise River Safety brochure which includes a map, safety tips and FAQs. All bridges will remain open on the Boise Greenbelt. The Greenbelt from Shoreline Park at the Idaho Fallen Firefighter Memorial is open so commuters can travel up and over the Trestle Bridge and continue on to N. Orchard Street. Baggley Park and sidewalks that the City of Boise maintains remain open.

  2. How long will the closures along the Greenbelt last? Sections of the Greenbelt will be closed until river flows decrease. Current Boise River flows are making conditions extremely dangerous for people and pets. Because of this winter’s deep snow pack, these conditions are expected to remain into June.  Boise Parks and Recreation staff members closely monitor conditions on the Greenbelt daily, and close off sections that are flooded and/or unsafe to navigate. We ask that Greenbelt users obey all posted signs and use corresponding detours when a section of the Greenbelt is closed. Safety of our residents is always top priority. Once water levels drop, sections of the Greenbelt will be opened as they become safe to use once again.

  3. Could I be cited for being on a closed Greenbelt path? Yes, a person can be cited if they are found on a closed section of the Greenbelt. However, the City of Boise’s main goal is education. Anyone found in a closed area will be asked to leave for their own safety.

  4. Who maintains the Boise River Greenbelt? The Boise River Greenbelt is a partnership between the city of Boise, Garden City, the city of Eagle, Ada County and the Idaho Foundation for Parks and Lands. Each is responsible for the care and maintenance of Greenbelt paths within its jurisdiction. The city of Boise maintains more than 25 miles of paved paths and trails within city limits.
    1. Learn more about the Boise Greenbelt
    2. Learn more about the Garden City Greenbelt
    3. Learn more about the Eagle Greenbelt
    4. Learn more about Ada County Parks and Waterways
    5. Learn more about the Idaho Foundation for Parks and Lands

*Additional River Rescue Information*

According to the Public Safety Emergency Response Cost Recovery Ordinance Section 7-02-01 through 7- 02-07, Boise City may impose a charge to recover costs incurred by the City for responding to a rescue on the river.

7-02-02 States: “Rescue emergency means a public safety or fire emergency incident resulting from a person or persons knowingly entering any area that has been closed to the public by competent authority for any reason, where such closure is posted by sign, barricade, or other device, and an emergency response such as a search for or rescue of such person results from the entry. For example, a rescue emergency would arise when the Boise River is flowing at a cubic foot per second level such that an authorized State, County, or City official declares the river closed to floating or rafting, the entry points are signed or otherwise posted as closed, and a person ignores the closure and a search and/or rescue results from the entry.”