Ditch Lining: the Water Right Issue
| Publication year | 1992 |
| Pages | 1155 |
| Citation | Vol. 21 No. 6 Pg. 1155 |
1992, June, Pg. 1155. Ditch Lining: The Water Right Issue
Agricultural irrigation accounts for 92 percent of all water diverted in Colorado and 95 percent of all water actually consumed.(fn1) Irrigation water is typically transported from the stream to fields through earthen canals and ditches. As much as from 30 to 35 percent of the water diverted is lost as ditch seepage before the water ever reaches the field. Even assuming an average ditch loss of only 20 percent, approximately 2.8 million acre-feet of water per year (approximately ten times the annual yield of Denver's water system) leaks out of ditches in Colorado.(fn2)
Developing new sources of water through large projects such as Two Forks Reservoir is increasingly difficult given the financial, environmental and political hurdles which are involved. Instead, legislators and the public are looking toward conservation measures to use Colorado's existing water resources more efficiently. One possible measure is to line irrigation ditches to prevent seepage loss. However, this seemingly simple solution raises a host of complicated legal issues which have not yet been resolved.
Ditch losses are often thought of by the public as waste---water which serves no useful purpose and which could provide a vast new water supply at little cost or environmental impact. Overlooked is the fact that although some of the ditch losses are indeed "lost" to the river system through evaporation or consumption by natural plants, most of the water eventually returns to the stream as groundwater inflow and provides water for diversion by downstream appropriators.(fn3) One man's "waste" can quite literally be another man's source of water.
The issue of whether water "saved" by ditch lining can be used or sold by the original appropriator, or whether it belongs in some fashion to downstream appropriators who historically may have relied on it to satisfy their own water rights, has not been addressed by the Colorado courts or legislature. Indeed, several conflicting lines of authority exist which point to different conclusions. Each is discussed briefly below.
A water right cannot be changed in Colorado to a new point of diversion, type of use, place of use or otherwise if the change will result in material injury to other water rights.(fn4) This "no injury" rule is also sometimes expressed as the right of junior appropriators "to the continuation of stream conditions as they existed at the time of their appropriations."(fn5) Changes which result in an "expansion of use" or a higher "duty of water" are prohibited.(fn6)
One well-established consequence of the no injury rule is that downstream water rights are entitled to a continuation of historic groundwater return flows if an irrigation water right is changed to a new use or place of use.(fn7) Groundwater return flows are the waters which seep into the ground and make their way back to the stream following application of water to a field---typically 30-50 percent of the amount of water applied. Usually, a portion of an irrigation water right which is changed to a new use must be left in the stream or stored for later release in order to maintain the historic amount and timing of irrigation return flows. Similarly, where a ditch is lined, the historic amount of ditch loss could be required to be left in the stream for use by downstream appropriators.
Colorado cases which apply the no injury rule have involved return flows from irrigated fields, not ditches. However, downstream appropriators may well argue by analogy that they are entitled to a continuation of ditch seepage (or, if the ditch were lined, to have a like amount of water left in the stream), if this seepage historically has been relied on by them to help satisfy their water rights.(fn8) This is particularly true where the ditch liner seeks to change the water saved to a new use or use it to irrigate additional acreage.
As an extension of the no injury rule, Colorado courts have held that once water is applied for irrigation, groundwater return flows that start back toward the stream are not subject to independent
appropriation. For example, in Ft. Morgan Reservoir & Irrigation Co v. McCune,(fn9) the original appropriator tried to capture the seepage from its reservoir by constructing a collection ditch below the reservoir. The Colorado Supreme Court held that as soon as the reservoir seepage starts toward the river, it constitutes part of the river and is not subject to recapture by the original appropriator.(fn10) Once the reservoir company lost control of the water, the water had to be allowed to return to the stream for the benefit of other appropriators in the order of their priorities.(fn11)
Water characterized as wastewater is treated differently from groundwater return flows. Wastewater is considered by the courts to be water which remains on...
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