Big Thompson River Forecasting

Eastern Colorado Area Office

• Manages projects local to Colorado’s Front Range

• Numerous activities and responsibilities

• Two main projects:– Colorado-Big

Thompson– Fryingpan-Arkansas

The Eastern Colorado Area Office in Loveland, CO

The Colorado-Big Thompson Project

Willow Creek Dam and Reservoir

The Colorado-Big Thompson Project

Three Lakes Collection System

Granby Dam, Reservoir and Farr Pump

• Largest reservoir• Serves as “savings

account” for project• One dam, three dikes• Releases to Colorado

River

The Colorado-Big Thompson Project

Shadow Mountain Reservoir and Grand Lake

Shadow Mountain Reservoir near the dam, the “boatable” canal, and Grand Lake clarity

The Colorado-Big Thompson Project

Alva B. Adams Tunnel

• Logistical solution

• Built 1940-47• 13.1 miles long• Under RMNP• 9.5 ft in diameter

The Colorado-Big Thompson Project

The Colorado-Big Thompson Project

The Colorado-Big Thompson Project

The Colorado-Big Thompson Project

Natural Inflow can be Skimmed

Limited Capacity / High Variability

Big Thompson Forecasting Project

• CHPS FEWS System• Natural Inflow to Lake Estes• Natural Flow on North Fork at Drake• Big Thompson River at Mouth of Canyon

• Forecasts• 1-hr Timestep• Short-term• Ensembles

Big Thompson Forecasting Project

• Implemented by Riverside• Operated 2013 by ECAO• Transferred to MBRFC in 2014• Partnership for Forecasting

• MBRFC—Day-to-day forecasting and maintenance

• ECAO—Occasional forecasting and scenario investigation

Thank you and Questions