NorthPlatteBasinWaterSupplyandNeedsReport

• Basin Roundtable: North Platte
• Title: Water Supply & Needs Report for the North Platte Basin
• Date: 6/1/2006
• Author: CDM
• Basin Roundtables - Doc Type: Needs Assessment Documents

Section 5
Consumptive Water Needs in the North Platte Basin
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South Platte

Mansas

98,000
38%

Figure 5-7
Projected Increase in Combined Gross M&I
and 551 Demand (AFY) and Percent
Increase from 2000 to 2030 by Basin

Similar to the population patterns described earlier in this
section, rates of M&I water use increases over the
30-year planning period are generally higher for the West
Slope basins than for the Front Range. However, the
bulk of the increase in water uses in terms of AFY will be
in the South Platte and Arkansas Basins, which together
represent about 80 percent of the total projected
increase in Colorado's gross M&I and SSI demands.

High and low estimates were also developed around the
baseline M&I and SSI water use projections described
above. Results of the high and low analysis are
presented on a basin basis in Figure 5-8. These values
represent the range of demands that might be expected
to occur in each basin in 2030. Enhanced conservation

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(') 1,400,000
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<: 1,200,000
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:J 1,000,000

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Oii 200,000
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Figure 5-8
Range of Potential Gross M&I and 551 Water Use in 2030

CONI

5-10

efforts that could further reduce the "low" water use
projections were considered in the options evaluation
phase as described in Section 9.

5.3 Projected 2030 Agricultural
Demand

Projections of 2030 agricultural demands and supporting
data are presented in Table 5-8. As a result of the
estimated potential changes in irrigated acres,
agricultural demands and their associated gross
diversions are shown as decreasing in the Arkansas,
Colorado, Gunnison Rio Grande, and South Platte
Basins. Demands in the Dolores/San Juan/San Miguel
and Yampa/ White Green Basins may have a net
increase if additional agricultural supplies are developed
to provide for the increase in irrigated acres.

A summary of total projected Colorado agricultural use
relative to M&I and SSI demands is shown in Figure 5-9.
As can be seen, agricultural use is expected to still
comprise the majority of these uses in 2030.

2%

iii Agricultural
ID M&I
. SSI

Figure 5-9
Relative Proportions of Agricultural, M&I,
and 551 Water Use in 2030

To better anticipate future conditions, it is helpful to
examine existing supply and demand. There are a
number of factors that impact the calculation of water
shortages such as the relative priority of water rights, the
physical supply of water available for diversion at any
given point, and irrigation practices. These factors are
discussed in greater detail below. First, under the
Colorado prior appropriation system, water is allocated
based on the priority of the water right, so that during
times of average to less than average streamflows, some
water rights will not be in priority, resulting in a shortage
of water to meet irrigation water requirements.

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