SPDSS_Task53-3_Assign Key Climate Information to Irrigated Acreage and Reservoirs

• Title: SPDSS Task 53.3 - Assign Key Climate Information to Irrifated Acreage and Reservoirs
• Description: This memorandum presents the general approach for the following Task 53 subtasks: 1. Assign key climate stations to geographic areas for the SPDSS modeling efforts. 2. Estimate average monthly reservoir evaporation rates for geographic areas.
• Decision Support - Doc Type: Task Memorandum
• Date: 2/1/2006
• DSS Category: Consumptive Use
• DSS: South Platte
• Basin: South Platte
• Contract/PO #: C153954
• Grant Type: Non-Reimbursable
• Bill Number: SB01-157, HB02-1152, SB03-110, HB04-1221, SB05-084, HB06-1313, SB07-122
• Prepared By: Leonard Rice Engineering

Table 2
Average Monthly Gross Evaporation Distribution
Elevation (ft) Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Below 6,500 3.0% 3.5% 5.5% 9.0% 12.0% 14.5% 15.0% 13.5% 10.0% 7.0% 4.0% 3.0%
Above 6,500 1.0% 3.0% 6.0% 9.0% 12.5% 15.5% 16.0% 13.0% 11.0% 7.5% 4.0% 1.5%
Table 3
Estimated Average Monthly Gross Reservoir Evaporation
(Inches)
Water District Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Total
1-Upper 0.43 1.30 2.61 3.91 5.43 6.74 6.95 5.65 4.78 3.26 1.74 0.65 43.46
1-Lower 1.41 1.65 2.59 4.24 5.65 6.83 7.07 6.36 4.71 3.30 1.88 1.41 47.11
2 1.31 1.53 2.40 3.93 5.24 6.34 6.55 5.90 4.37 3.06 1.75 1.31 43.70
3-Upper 0.37 1.11 2.22 3.34 4.63 5.75 5.93 4.82 4.08 2.78 1.48 0.56 37.07
3-Lower 1.19 1.39 2.19 3.58 4.78 5.77 5.97 5.37 3.98 2.79 1.59 1.19 39.79
4-U er 0.36 1.07 2.14 3.22 4.47 5.54 5.72 4.65 3.93 2.68 1.43 0.54 35.75
4-Lower 1.16 1.35 2.12 3.47 4.62 5.58 5.78 5.20 3.85 2.70 1.54 1.16 38.52
5-U er 0.35 1.06 2.13 3.19 4.43 5.49 5.67 4.61 3.90 2.66 1.42 0.53 35.43
5-Lower 1.15 1.35 2.12 3.46 4.62 5.58 5.77 5.20 3.85 2.69 1.54 1.15 38.49
6-U er 0.36 1.07 2.14 3.20 4.45 5.52 5.69 4.63 3.91 2.67 1.42 0.53 35.58
6-Lower 1.15 1.35 2.11 3.46 4.61 5.57 5.77 5.19 3.84 2.69 1.54 1.15 38.44
7-Upper 0.36 1.07 2.14 3.22 4.47 5.54 5.72 4.65 3.93 2.68 1.43 0.54 35.73
7-Lower 1.19 1.39 2.19 3.58 4.77 5.77 5.97 5.37 3.98 2.78 1.59 1.19 39.78
8-Upper 0.38 1.15 2.31 3.46 4.81 5.96 6.15 5.00 4.23 2.88 1.54 0.58 38.45
8-Lower 1.25 1.45 2.28 3.74 4.98 6.02 6.23 5.61 4.15 2.91 1.66 1.25 41.52
9-Upper 0.37 1.10 2.19 3.29 4.57 5.66 5.85 4.75 4.02 2.74 1.46 0.55 36.54
9-Lower 1.20 1.40 2.21 3.61 4.82 5.82 6.02 5.42 4.01 2.81 1.61 1.20 40.13
23 0.39 1.16 2.32 3.49 4.84 6.00 6.20 5.03 4.26 2.90 1.55 0.58 38.72
47 0.38 1.13 2.27 3.40 4.73 5.86 6.05 4.91 4.16 2.84 1.51 0.57 37.80
48 0.37 1.11 2.23 3.34 4.64 5.76 5.94 4.83 4.09 2.79 1.49 0.56 37.15
64 1.46 1.71 2.68 4.38 5.85 7.06 7.31 6.58 4.87 3.41 1.95 1.46 48.72
76 0.40 1.19 2.37 3.56 4.95 6.13 6.33 5.14 4.35 2.97 1.58 0.59 39.56
80 0.36 1.07 2.13 3.20 4.44 5.51 5.69 4.62 3.91 2.67 1.42 0.53 35.54
Step 4: Distribute annual precipitation to monthly
Monthly precipitation data for key climate stations were collected and filled under Task 53.2.
Average annual precipitation (100% effective) estimates developed in Step 2 above were
distributed monthly based on data from designated key climate stations. The key climate stations
selected to represent each water district or portion of a water district are shown in Table 4.
These representative key climate stations were selected based on existing reservoir locations.
The resulting average monthly total precipitation estimates are provided in Table 5.
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