• Intervening flow forecasts (inflow between Lake Mead and Lake Powell)• Inflow forecasts needs between Davis & Parker – Havasu operational limits• Forecast needs below Havasu to Imperial Dam• Precipitation forecasts for irrigators (Imperial Valley)

• Forecast ability for inflow between Davis and Parker ?• Requirement / ability to model downstream to Imperial Dam.• Availability of projected releases from Reclamation for Mead, Havasu, and Mohave.• Identify relevant rainfall that might affect Imperial Valley irrigation (WFO Chat).• Determine the best number to represent upper basin SWE % of average.

• Communicate differences in Powell to Mead intervening flow means to Reclamation group in Boulder, CO for further discussion• Assist CBRFC in determining what diversions/data exist downstream of Mohave applicable to future modeling efforts.• Review possibility of funding streamflow gages on the Sacrament and Piute washes including adding additional precipitation gages in these areas.• Coordinate with WFO Las Vegas for NWS Chat access ?

CBRFC-Lower Reclamation Primary Forecast Issues:

Outstanding CBRFC Action Items:

Outstanding Reclamation Action Items:

Lower Colorado Basin – USBR Items

Intervening Flow Forecasts: Lake Powell to Lake Mead

Colorado River - Lake Powell to Diamond Fork

Little Colorado

Paria River

Virgin River

Muddy Creek

Muddy3% Virgin

22%

Paria2%

Little Colorado18%

Havasu5%

Kanab1%

Powell to GC18%

GC to Diamond31%

Annual DistributionInflow between Powell & Mead

NWSRFS Modeled River Segments

Best Skill

Lake Mead Intervening Flow – 2010 Forecasts & Observed

Forecast Calculations:

Colorado @ Diamond Ck (CDCA3) + Virgin above Overton (VLMN2) + Muddy near Glendale (MUDN2) – Colorado @ Lee’s Ferry (CLFA3)

Lake Mead Inflow (LKSA3) – Colorado @ Lee’s Ferry (CLFA3)LKSA3 = CDCA3 + MUDN2 + VLTA3 – CLFA3 + local flow

Observed Calculation:

Colorado @ Diamond Ck (CDCA3) + Virgin above Overton (VLMN2) + Muddy near Glendale (MUDN2) – Colorado @ Lee’s Ferry (CLFA3)

48 43 57 65 79 89 98 98 90 80 69 59

.36 .33 .37 .46 .53 .64 .80 .85 .70 .51 .51 .44

CBRFC monthly evaporation (KAF) Jan-Dec

Reclamation monthly evaporation coefficients (feet) Jan-Dec

Coefficients are multiplied by the average surface area of Lake Mead over the course of a month.

CBRFC Evaporation = CDCA3 + MUDN2 + VLMN2 – Change in Storage – Release – Las Vegas Wash + Southern Nevada Waste Water Diversion

Lake Havasu Local InflowNWSRFS Modeled River Segments

Calibration System:

Challenges:

Finding significant precipitation events during the calibration period (signal to noise ratio)

Possible Solutions:

Expand Precipitation gages on California side

Increase density of precipitation gages

Rate current Mojave County streamflow gages

Installation of streamflow gages on major washes between Davis and Parker Dams

Sacramento Wash (largest)

Piute Wash

Lake Havasu Local InflowNWSRFS Modeled River Segments

Primary Inputs

Observed river stage & reservoir release data

Observed Hourly Data

• Gage data (Mojave Co. ALERT)

• NWS Doppler Radar

Forecast Precipitation

• 6 Hourly QPF Data

Operational Forecast System:

Additional Operational Data Needs

Release schedule or pattern for reservoirs