2012-11-27_HYDROLOGY - M1979195

• Permit No: M1979195
• IBM Index Class Name: HYDROLOGY
• Doc Date: 11/27/2012
• Doc Name: SWSP
• From: OSE
• To: Denver Water
• Permit Index Doc Type: Hydrology Report
• Email Name: BMK
• Media Type: D
• Archive: No

Ryan Stitt
Denver Water NRC SWSP
November 27, 2012
Depletions
During WY 2013 consumptive use for the Hazeltine Reservoir will include evaporation of
groundwater within the reservoir boundary. The surface area of this exposed groundwater is
approximately 17.63 acres based on a 2010 aerial photography of the Reservoir location. A
system of dewatering pumps is in place to pump the water within the reservoir boundary directly
to the South Platte River. This operation is in place to maintain the water level in the reservoir
at or below the waterline necessary to allow the continued removal of material from the site. As
long as the slurry wall liner is approved so as to prevent the refill of the pit with groundwater, this
dewatering operation is not expected to produce lagged depletions to the stream system once
dewatering ceases.
Net evaporative depletions were calculated using a gross annual evaporation of 44
inches based on the NOAA Technical Report NWS 33, Map 3. The gross evaporation is
reduced by 10 inches for effective precipitation based on data from the Brighton weather station.
Based on an exposed groundwater area of 17.63 acres, the maximum unlagged evaporative
depletion on an annual basis is approximately 50 acre -feet per year.
Denver water has installed a ground water mounding drain around Hazeltine Reservoir.
This drain has the ability to outfall in the pre -81 pond previously described. Because this
ground water diversion is separate from the normal interaction of the pre -81 pond with the
ground water, and because Denver Water may use the mounding drain water for gravel pit
operations including dust control, fire control, and a concrete batch plant, all water delivered to
the pond will be metered and must be considered 100% consumptive with replacements made
at any time the site is subject to a call on the river.
The Integrated Decision Support Alluvial Water Accounting System (IDS AWAS) stream
depletion model using the Glover alluvial aquifer condition was used lag depletions to the South
Platte River using the following aquifer parameters: transmissivity (T) = 55,000 gallons per day
per foot, specific yield (SY) = 0.2, the distance from the centroid of the exposed ground water to
the river (X) = 1,470 feet, and the distance from the parallel impermeable boundary to the
stream (W) = 6,351 feet. This lagging analysis results in the following lagged depletion
percentages for water use at the Hazeltine Reservoir site:
Table 1: Lagged Depletions as Percentage of Consumptive Use
* Remaining lagged depletions are aggregated into the 30"' Month after the water use.
Page 3 of 8
As seen from the Table in the "Replacements" section below, the total lagged depletions for WY
2013 and WY 2014 is 48.69 acre -feet and 16.79 acre -feet, respectively.
Replacements
Depletions associated with this SWSP will be replaced using the portfolio of water rights
owned by Denver Water. Replacements will be aggregated with other replacement releases
required to be made by Denver Water as part of its normal operations. Denver Water is
responsible for providing the accounting to the Division Engineer for these operations. A
Month
1
Month
2
Month
3
Month
4
Month
5
Month
6
Month
7
Month
8
Month
9
Month
10
Month
11
Month
12
Year
1
0.160
0.246
0.123
0.067
0.046
0.033
0.027
0.023
0.020
0.018
0.016
0.015
Year
2
0.014
0.012
0.012
0.011
0.011
0.010
0.010
0.010
0.010
0.010
0.010
0.010
Year
3
0.010
0.010
0.010
0.010
0.010
0.010
0.016
*
0.000
0.000
0.000
0.000
0.000
Ryan Stitt
Denver Water NRC SWSP
November 27, 2012
Depletions
During WY 2013 consumptive use for the Hazeltine Reservoir will include evaporation of
groundwater within the reservoir boundary. The surface area of this exposed groundwater is
approximately 17.63 acres based on a 2010 aerial photography of the Reservoir location. A
system of dewatering pumps is in place to pump the water within the reservoir boundary directly
to the South Platte River. This operation is in place to maintain the water level in the reservoir
at or below the waterline necessary to allow the continued removal of material from the site. As
long as the slurry wall liner is approved so as to prevent the refill of the pit with groundwater, this
dewatering operation is not expected to produce lagged depletions to the stream system once
dewatering ceases.
Net evaporative depletions were calculated using a gross annual evaporation of 44
inches based on the NOAA Technical Report NWS 33, Map 3. The gross evaporation is
reduced by 10 inches for effective precipitation based on data from the Brighton weather station.
Based on an exposed groundwater area of 17.63 acres, the maximum unlagged evaporative
depletion on an annual basis is approximately 50 acre -feet per year.
Denver water has installed a ground water mounding drain around Hazeltine Reservoir.
This drain has the ability to outfall in the pre -81 pond previously described. Because this
ground water diversion is separate from the normal interaction of the pre -81 pond with the
ground water, and because Denver Water may use the mounding drain water for gravel pit
operations including dust control, fire control, and a concrete batch plant, all water delivered to
the pond will be metered and must be considered 100% consumptive with replacements made
at any time the site is subject to a call on the river.
The Integrated Decision Support Alluvial Water Accounting System (IDS AWAS) stream
depletion model using the Glover alluvial aquifer condition was used lag depletions to the South
Platte River using the following aquifer parameters: transmissivity (T) = 55,000 gallons per day
per foot, specific yield (SY) = 0.2, the distance from the centroid of the exposed ground water to
the river (X) = 1,470 feet, and the distance from the parallel impermeable boundary to the
stream (W) = 6,351 feet. This lagging analysis results in the following lagged depletion
percentages for water use at the Hazeltine Reservoir site:
Table 1: Lagged Depletions as Percentage of Consumptive Use
* Remaining lagged depletions are aggregated into the 30"' Month after the water use.
Page 3 of 8
As seen from the Table in the "Replacements" section below, the total lagged depletions for WY
2013 and WY 2014 is 48.69 acre -feet and 16.79 acre -feet, respectively.
Replacements
Depletions associated with this SWSP will be replaced using the portfolio of water rights
owned by Denver Water. Replacements will be aggregated with other replacement releases
required to be made by Denver Water as part of its normal operations. Denver Water is
responsible for providing the accounting to the Division Engineer for these operations. A