HYDRO24786

• Permit No: M1979195
• IBM Index Class Name: Hydrology
• Doc Date: 6/15/2001
• Doc Name: TEMPORARY SUBSTITUTE SUPPLY PLAN SUBURBAN SAND AND GRAVEL ROAD RUNNERS REST II GRAVEL PIT MLRB PN M-
• From: ENVIRONMENT INC
• To: DWR
• Media Type: D
• Archive: No

~ENVI~RONMEN T, INC. •
SUBURBAN $AND AND GRAVEL, CO
TEMPORARY BUPPLY PLAN
JUNE 1 5, 2001
• PARE 2
the size of the surface area is fairly constant due to the uneven nature of
the mine floor.
We used 25.0 acres as the lake surface area and based our net lake
surface evaporation on this amount. As before we have taken 69.77 acres of
dry up credit for the grass hay crop historically grown on the site. But
during analysis of the water available, we found that the Burlington Ditch
shares would provide a minimum of 64.03 ac-ft. Using a 65~ efficiency factor
suggested by Gary Witt of Wright Water Engineers, the amount is reduced to
41.62 ac-ft of water in a dry year. This number is used in the TSSP to
offset lake evaporative losses during the growing season. In this case the
Blaney-Griddle analysis shows only that the grass hay requires more water
than the ditch water can provide. This field has been removed as mining
progresses, freeing the ditch water for use in the TSSP.
Approximately 75.00 acres ± has been mined, that will be reservoir area,
any water that falls on this excavated area is channelled to the dewaterinq
pit and pumped to the river. This area was originally covered by the
irrigated field and native vegetation that has now been removed so there is
little or no vegetation present. Any precipitation that falls on the
excavated area goes directly to the pumps and is returned to the system
without being used by vegetation. To calculate the net lake evaporation the
total mined area (75 ac.) was multiplied by the adjusted annual precipitation
from Table C Column 5 to determine the amount of water needed for lake
evaporation from the proposed lake area (25 ac.). This is shown in Table A
Column 2. '
I have also attached copies of the most recent (1994 to 2000) diversion
records for the Burlington Ditch so the division has the last 30 years of
diversion records. This will bring those records current for your file. The
precipitation that falls on the entire stripped area flows into the water
area so credit was claimed from that area to offset the impacts evaporation
will have.
The tables attached show the monthly distribution of historic losses,
and future losses, and an exhibit showing Blaney-Griddle method of calculat-
ing consumptive uses by crops.
TABLE A, BALANCE FOR DRY UP -VS- ACTUAL LOSSES FROM LAKE AREA ON
DISTURBED AREA, is the most important, it is the final accounting table
showing the amount of makeup water we need to supply on a monthly basis. It
takes the final numbers found in Tabla B and Tablo F, to find the impact the
operation will have on the system. Based on the amount of water available
from the ditch there is adequate water available to meet the evaporation
losses from the 25.00 acre s+/- lake. Review will show water is available
for as many as 361 days each year. The same distribution percentages from
Guideline }'6 was used to calculate the amount of ditch water available for
makeup.
TABLE H, MONTHLY WATER LOSS RECAP FOR GRAVEL OPERATION, recaps the loss
and credit calculations done in TABLE C and TABLE D. It serves to show the
net amount of water used by the operation before any credits are applied from
supplemental water or as a result of crop dry-up. This table will serve as
the guide when the monthly reports are filled out.
TABLE C, AVERAGE ANNUAL NET LAKE EVAPORATION LOSS, is a table adapted
from the CRITERIA requirements. It shows the average annual evaporative loss
and average annual precipitation for the Brighton area. This table is used
to calculate the net loss on the lake area.