Agricultural Return Flows

Water Resource Engineer Applegate Group, Inc. Denver, CO.

By: Clay Good

Biography

Background • Irrigated Agriculture • Agricultural Production • Civil Engineering/Water Resource Engineering

Education • B.S. Soil and Crop Science - CSU • B.S. Civil Engineering – CSU

Work Experience Agricultural • Farm Management Consulting • Soil Fertility/Crop Growth Management

Water Resource Engineering • Water Rights • Floodplain Design and Analysis • Stream Restoration and Construction • Infrastructure Design

Did you know?

Introduction

Basics What are Ag return flows?

Analysis How are they used?

Use Why are they important?

Quick Colorado Water Right Lesson “Water is the lifeblood of Colorado, our source of life, our liquid gold.” -Water, CO’s Real Gold By: Dick Stenzel and Tom Cech “First in time, first in right” • Prior Appropriation Doctrine

Beneficial Use •Basis, measure and limit of a water right •Lawful appropriation that employs resonably efficient

water use practices •Augmentation •Commercial/Industrial •Domestic •Irrigation •Oil and Gas Production

Water Right Use õ True measure of a water right is how it has been used for

BENEFICIAL PURPOSES.

õ At time of adjudication, applicant must: õ Demonstrate diversion of specified amount of water

and the application of that water to a beneficial use.

õ Irrigator diverts water õ Water commissioner records õ Over time, each owner diverted the water and irrigated the decreed acres.

õ Over the years, the right’s full measure (entitlement) was established.

Colorado Water System

Agricultural Use Furrow Irrigation • Flood

Sprinkler Irrigation • Groundwater • Surface Water via Pond Diversion

Drip Irrigation • Vegetable, high price commodities

Typical Farming Application

q Flood Irrigation q 50% Consumed q 50% Loss q Runoff q Evaporation q Deep

Percolation q Returns to

stream q Rate of

return q Volume not utilized referred to as Return Flows

Return flow

q System Operation

q Importance

Historical Use

Historical Importance •River/Stream Benefited from Return

Flows •Downstream water users diverted

these return flows •Consuming some of these Return

Flows

Downstream • Generate

individual return flows

• Thousands of farms

• Hundreds of thousands of acres

• A great deal of water!!

Sold! •Agricultural to Industrial Change of Use

Change Application •Use, place of use, place of diversion, means of diversion •Must prove no injury •Must demonstrate lawful historical use of water rights

Lawful Historical Use q To accomplish this:

1) Historical Consumptive Use analysis a) Assemble diversion records b) Interview irrigator, attain FSA records,

review aerial photos to verify crops grown c) Consumptive Use associated with

historical use of right d) Return Flow volume and timing

a) Determine timing of these return flows

Engineering Results

• On average • The farmer diverted 110 AF from river

• 50 AF CU • 10 AF Ditch Loss • 40 AF Subsurface Returns • 10 AF Surface Returns

Will report to new owner

Factory Owner Use

• Amount factory owner can divert into factory and consume with NO injury to other water users

50 AF of water each year – CU Amount

• Never benefited river historically • It was historically consumed by irrigated crops • Continued consumption in priority will have no

negative effect

This CU is portion of farmers water right that contains value

Conclusion

•No, the historic return flow patterns would be altered, and those relying on these return flows downstream would be injured.

Can the factory owner divert this 50 AF only and utilize when he/she wants?

•To utilize 50 AF of CU •Must also divert the remaining 60 AF

•And return it back to the river at the same time/amount as historically done

This all means that:

•Factory may only divert May-October Diversion times?

•Historic accrual of return flows •Factory owner must follow same return schedule •Ditch diversion only during irrigation season •Must store, or gain additional leases to cover winter-time return

flow obligations

Winter return flows

Questions?