LADWP offers update on runoff management

Press release

LADWP Runoff Preparation and Management Continue in the Eastern Sierra Region as Water Flows Increase – UPDATE 3

The Los Angeles Department of Water and Power (LADWP) continues to work proactively to handle the massive runoff water resulting from this year’s near record snowpack in the Eastern Sierra Nevada Mountains.

These efforts are in partnership with Inyo County, the Inyo Sheriff’s Department, Bishop Police Department, Cal-Trans, Southern California Edison and others, as a member of the Inyo County Interagency Emergency Preparation team.

Work to prepare for the anticipated high water flows began in late February. The efforts have been assisted by an Emergency Declaration from the Mayor of the City of Los Angeles to allow LADWP to take immediate steps to protect infrastructure and aid in managing flood waters while also protecting public safety. Inyo County issued a similar declaration.

LADWP is concerned by the potential of water overflow in and around the towns and communities of the Eastern Sierra and is actively providing assistance in preventing and controlling runoff that could impact the public. Emergency assistance will be provided on lands throughout the valley should flooding threaten the property of a partner agency or the public.

Further, LADWP is advising the public to be aware that swift flowing water is causing increased turbidity and organic matter in the river. Decomposition of this organic material will result in low dissolved oxygen levels and as a result fish stress is expected during this period of high runoff.

LADWP is minimizing extra flow in the Owens River as much as possible and will collect and dispose of deceased fish as quickly as possible.

In order to keep the public informed of the steps being taken to manage runoff to the greatest extent possible and minimize the impact to dust control measures, LADWP will issue regular updates of its runoff management efforts. The following is the third update to the runoff management activities undertaken to date.

Emergency Runoff Management Activities undertaken by LADWP from May 18 to June 21, 2017, include:

Water Spreading

To maximize the beneficial use of runoff water to the fullest extent, LADWP is spreading water throughout the aqueduct system to replenish local groundwater aquifers. Current spreading is moderate and will increase as runoff occurs in larger quantities later this summer. The amount of water spread to date, includes:

 

  • Long Valley –                                               4,800 AF
  • Pleasant Valley Reservoir to Tinemaha Reservoir –       56,000 AF
  • Tinemaha Reservoir to Haiwee Reservoir –                    54,000 AF
  • South of Haiwee Reservoir –                                               6,000 AF

 

Total Water Spread                                                                  120,800 AF

 

Maintenance and Construction Activities

Mono Basin to Bishop

Long Valley area:

  1. Diversion structures on Convict and McGee creeks are continuously being cleaned and maintained for water spreading and irrigation needs
  2. Rock Creek sand trap and bypass intake at Toms Place continuously being cleaned and maintained.
  3. Sand bagging activities have commenced

Round Valley area sand traps, measuring stations and diversions have been cleaned by hand crews and or equipment. Work in the area will be on going throughout the run off event to maintain these structures.

  1. Pine Creek flume is being manned 24/7 during the duration of high flows.

Bishop Area to Tinemaha Reservoir

Continue to maintain existing spreading ponds and diversion structures primarily in the Laws/Five bridges area which are fed by the McNally Canals.

  1. The McNally Canals and the McNally extension east of Hwy 6 are running water near capacity for the dual purpose of irrigation and spreading.

Maintenance and repair work will be continuous during runoff on the primary canals, ditches and ponds in the Bishop area.

  1. Mowing of the Bishop Creek Canal and associated diversions has started and will continue as needed throughout the summer.
  2. The Rawson and Ford Rawson Canals are near capacity for the purpose of irrigation and spreading. Further maintenance is scheduled on both canals to increase capacity and spreading potential.
  3. Both the Collins and A.O. Collins Canals are near capacity for the purpose of irrigation and spreading water.

Big Pine area work is ongoing:

  1. Baker creek sand traps, diversion structures and ponds are continuously being cleaned.
  2. Big Pine Canal has been cleaned, mowed and is running near capacity. Further maintenance will be needed throughout the summer to maintain capacity once aquatic growth begins to restrict flows.
  3. Tinemaha and Red Mountain Creek diversions are spreading.

Tinemaha Reservoir through Haiwee Reservoir Complex

Work here includes operating and maintaining spreading infrastructure constructed in 1969.

Black Rock Area:

  1. Blackrock Ditch diversions, Stevens Ditch, Thibaut Ponds and ditches are being utilized and maintained on a continuous basis.

East of Owens river canals.

  1. McIver ditch from East of Goose Lake to south of Mazourka road.
  • 10.6 miles of canal with 5 miles of percolation ponds in operation
  1. Eclipse/East Side ditch from Mazourka road to south of Owenyo area.
  • 12.5 miles of canal and spreading ponds operating at near capacity.

Diversions on Alluvial Fans:

  1. All diversions, spreading berms and settling ponds operating near capacity.

LORP Intake:

  1. Debris and sediment removal continuous.

Los Angeles Aqueduct:

  1. Intake – Maintaining water way capacity – Debris and sediment removal continuous.
  2. Unlined section – Ongoing sediment and aquatic growth removed when personnel and equipment is available.
  3. Lined section to Alabama Gates – Maintaining water way and cleaning sand traps continuous.

Owens Lake

Lower River Branch Diversion (Super Sacks, etc.)                   (100% complete)

Vegetation Tamping (Acres)                                                          (100% complete)

LORPS (K-Rail, Sand Bags)                                                          (100% complete)

LORPS Dike Expansion                                                                 (100% complete)

T29 Berm Armoring (Rip Rap)                                                       (100% complete)

T36 Berm Armoring (Rip Rap)                                                       (100% complete)

Zonal Mainline Protection                                                              (88% complete)

Western HDPE Pipe Protection                                                    (100% complete)

Stream Clearing  at LORP Pump-back Station                          (100% complete)

Mojave to Los Angeles

Currently repairing/rebuilding Maclay Highline                         (50% complete)

Equipment Staging

  • All requested heavy equipment has been rented and received based on forecasted needs. Equipment is performing preparation tasks, will be staged during spreading and cleaning operations.

Safety Signage

LADWP has posted safety message signs at public access points near swift water locations. In addition to posting safety signage, LADWP has also taken out advertisements in all local media advising the public to practice water safety during this period of high runoff.

LADWP encourages the public to practice general water safety throughout this period of high runoff. To obtain information on local floods or flood risks, residents are encouraged to sign up for CODE RED through the Inyo County Sheriff’s Office.

To report flooding, please contact the Sheriff’s Office at 760-878-0383. Be prepared to tell the Sheriff’s Dispatcher the exact location of the flooding and if the water threatens structures, animals, land or roadways. If water threatens human life, dial 9-1-1 immediately.

 

 

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