A new report offers reasons behind the Boise River's high water levels, which are expected to last for another week after rainfall and as temperatures rise next week.

The Natural Resources Conservation Service, a division of the U.S. Department of Agriculture, has released the new water supply outlook report, which attributed the rise in water levels to March snowmelt.

The NRCS wrote:

Mountain temperatures reached 70-75 F for several consecutive days and valley temperatures reached into the low 90s F in Boise. Using long-term valley weather station data as a gauge, this heat wave was likely the hottest in April since 1875. With the snowpack ripe, this heat created record high melt rates of an inch/day in April.

Heavy snowmelt was followed by colder temperatures and heavier-than-expected rainfall, with the river reaching a height of 10.86 feet as of this morning; flood level is considered 10.1 feet. The USGS has a webcam for viewing the river here.

• USGS
• The USGS shows high levels and fast currents on the Boise River.

With heavier than expected rainfall and snow melt, the Boise River is running above flood stage, according to the National Weather Service.

• Boise State University
• A view of the Capitol Boulevard Greenbelt underpass.

Boise Department of Parks and Recreation has since closed sections of the Greenbelt deemed unsafe. At major bridges and other low-lying areas, pedestrians and cyclists are met with detour signs near the quickly moving water, currently at more than 8,000 cubic feet per second at the Glenwood Street bridge.

Pedestrian tunnels beneath Ninth Street, Capitol Boulevard, and Broadway Avenue are unusable. The section from Main Street to Shoreline is currently closed, with posted detours along city streets.

• City of Boise
• Boise Parks and Recreation has closed sections of the Greenbelt because of flooding.

The river is currently at a height of 10.75 feet, above the flood stage of 10.1 feet. The Parks Department website has a full list of Greenbelt closures in the Boise area.

The National Weather Service office in Boise has sustained its flood warning for the Boise River at Glenwood Bridge.

At 8 a.m., the Boise River was reported to be 10.47 feet, just above the flood stage of 10.1 ft.. Additionally, the river was running at approximately 7.53 cubic feet per second and the flows are expected to get only greater. Discharge from the Lucky Peak Reservoir is expected to increase both today and Wednesday, targeting a flow of 8,000 cfs at the Glenwood Bridge. The flood flow is 7,000 cfs.

Law enforcement is expecting minor flooding at several sections along the river, including the Greenbelt, Eagle Island and other low spots.

When the Boise River hits 8,000 cfs, sometime on Wednesday, it will be the highest Boise River flow in more than a decade. The record of 9,840 cfs was set in June 1983.

Following a week of heavy showers, the Boise River is running near its flood threshold stage this morning.

The National Weather Service Office in Boise issued a flood warning for the river until further notice. Flows at the Glenwood Bridge are expected to hit 7,400 cubic feet per second by this afternoon.

The U.S. Army Corps of Engineers warns that an addition 500 cfs was scheduled to be released today due to near-capacity in the Boise River reservoir system.

Boise Parks and Recreation officials have closed down the Greenbelt at the Broadway Avenue and Main Street tunnels due to anticipated high water. Two other sections—the walking trail from the Cottonwood Apartments east to Bown Crossing and the Loggers Creek footbridge between Leadville Avenue and the ParkCenter Bridge—have been closed since mid-April.

The long-range forecast calls for on-again, off-again chances of showers or thunderstorms until next Friday.

Those anxious for summer and the prime months for floating the Boise River may have to wait before donning the water wings.

On March 30, the Bureau of Reclamation and the U.S. Army Corps of Engineers will increase flows from Lucky Peak Dam to help reduce the risk of springtime flooding. As the snowpack melts and the rainy weather kicks up, Boise area reservoirs are at higher-than-average levels, currently at 76 percent of capacity.

By April 3, river flows will increase 500 cubic feet per second, with a flow rate of 6,500 cfs at the Glenwood Bridge gauge, which is more than double the flow rate a month ago. A flow rate of 7,000 cfs is considered flood-stage level.

Officials also said that flow could also increase in the coming months as more water pours into the river system. With the cold water, increased depth and velocity of the river, they advise citizens exercise extra caution near the water.

The Boise River is inching up, while a lot more precipitation is forecast for the week ahead.

As of 7:45 a.m., the Boise River was at 9.14 feet, with flood stage set at 10 feet.

Some sections of the Greenbelt have been closed by high water. The Bethine Church River Trail from the Cottonwood Apartments east to Bown Crossing and Loggers Creek Bridge from Leadville Avenue east past the West Parkcenter Bridge have been closed to pedestrians.

The forecast calls for steady showers or a chance of showers through Friday.

The City of Boise has received new permits from the Environmental Protection Agency providing guidelines to radically reduce the amount of phosphorus that makes its way to the Boise River.

Last summer, BW first told you about the new guidelines that include never-before-seen restrictions on phosphorous and water temperature. As a result, the city bumped up sewer rates to pump $5 million into Boise's wasterwater treatment facilities, as part of a long-term plan that could cost up to $50 million over the next five years.

Under the new permits, issued this week, Boise officials promised the EPA to limit mercury and ammonia discharges and release cooler water from treatment plants into the river.

As we reported in 2011, Boise needs to bring its phosphorous discharges down from approximately 1,100 pounds per day to approximately 15 pounds daily.

"Our permits have never had a limit on phosphorous before," Paul Woods, Boise's Environmental Division manager, told BW last summer. "This is brand new, and it's a very big issue."

How does Boise reduce its phosphorous by such a large margin? Under a two-part plan, the city first began something called its Enhanced Biological Nutrient Removal. Secondly, the plan includes the Dixie Drain, a 49-acre parcel of land between Notus and Parma. You can read about it here.

Last summer, City of Boise officials were prepared to float a plan that would have given Boise Police more authority in handing out tickets to people jumping from bridges over the Boise River.

But Mayor Dave Bieter received a wave of pushback from the community—many of the comments invoked the public's earliest childhood memories of bridge jumping. The proposed river-jumping ordinance was quickly yanked from the City Council agenda. The mayor and council immediately directed staff to conduct further study on any proposed changes to river use ordinances.

This Tuesday, when Bieter and the council huddle during a work session, Police Chief Mike Masterson will propose to "decriminalize all river jumping from bridges or other riverbank locations, unless the jumper lands within 50 feet of a river floater, which would be an infraction." The proposal would also set designated spots along the Boise River to allow for boogie boarding.

Currently, it's a misdemeanor for "any person to jump from, throw or drop any object or another from any bridge." Masterson said because many of the jumpers have been minors, the process of bringing charges and petitioning the violators into juvenile court "is cumbersome and time consuming."

The U.S. Army Corps of Engineers and the Bureau of Reclamation announced today that flows coming out of Lucky Peak Dam on the Boise River will start increasing in an effort to reduce the flood risk once the snow runoff begins in earnest later this spring.

The reservoirs which feed the Boise River are at roughly 73 percent capacity, so to make room for more water, river flows will increase by 66 cubic feet per second each day staring on Wednesday. Officials estimate that flows will reach roughly 3,000 cfs at the Glenwood Bridge gauging station by Friday, March 9. Flood stage is considered 7,000 cfs.

While there are no other increases planned as of yet, it all depends on how fast the snow pack melts this year. In the meantime, use extra care around the river, which will not only be running high and fast, but extremely cold as well.

Ada County Sheriff's deputies braved the frigid waters of the Boise River today in an exercise to help law enforcement officers make smart decisions when they have to battle the elements while rescuing boaters or rafters. Bystanders shuddered while the 50-degree water rushed over willing participants. Deputies had to jump in, go completely submerged, and then bring their heads above water for two and a half minutes. After that, they had to secure a life vest on themselves and remain in the water.

Sgt. John Harris of the Ada County Sheriff’s Office volunteered first to take the plunge.

“Boy is that cold,” was all he could say while trying to catch his breath. Harris said his hands and arms instantly began tingling, and it took him 30 seconds before getting his breathing under control.

“I felt like I was hyperventilating,” Harris said, still dripping wet on the river bank.

Ada Sheriff’s Lt. Scott Johnson said it’s important that officers get their brains and thought processes under control in these situations. Many people think hypothermia is the biggest risk in cold water, but more people die from drowning after the bitter temperatures send them into shock, he added.