2015-05-12_HYDROLOGY - M2003091 - Laserfiche WebLink

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Mr. David Heintz Page 3 of 10 Duckworth SWSP May 6, 2015 September 2013 and will remain full of water through the terms of this SWSP. Therefore, although the Applicant anticipates dewatering into the Cottonwood Pond, the Applicant also request the ability to send dewatering water to the Lighthouse Cove Pond to the north of the Duckworth Pit, or pump the water to the Smith and Emmons Ditch to be transported back to Boulder Creek. Dewatering shalt be metered so as to account for water delivered to the Cottonwood Pond, the Lighthouse Cove Pond, or the Smith and Emmons Ditch. The Lighthouse Cove Pond ("LCP") is an unlined ground water pond (welt) owned by the Lighthouse Cove Development. This pond was created from sand and gravel operations under DRMS permit no. M-1983-099 and was known as the Groom Addition. DRMS released this pit in 1993. A pre -1989 augmentation agreement between the gravel pit operator and the District 6 Water Users Association provides for replacement of evaporation from the LCP. Given the size of the pond and the rate of dewatering, the dewatering operation is not expected to increase the exposed surface area of the pond by any measureable amount. The LCP is approximately the same distance from Boulder Creek as is the Duckworth site and therefore any lagged depletions associated with dewatering that is discharged into the LCP is assumed to be offset by the lagged recharge credits generated by the same operation. This SWSP does not confer on Applicant the right to use facilities or structures not owned by it. MMM has stated they are in the process of obtaining permission from Lighthouse Cove Development to use their pond and they shall not divert any water to that pond until the appropriate legal arrangements are made. Any dewatering water placed into LCP cannot be used for irrigation or any other purpose by Lighthouse Cove Development or others, and must be allowed to accrete to the stream. The provision in the SWSP allowing LCP to be used as a recharge pond may not be continued in SWSP renewals should it be determined by the water commissioner or division engineer that water within LCP is being diverted for use or the accounting is not adequate to show that recharge of dewatering is occurring. MMM has obtained permission from the Smith and Emmons Ditch Company to run dewatering water in the ditch and MMM plans to construct a waste way for the Smith and Emmons Ditch which will run from the ditch due west and directly back into Boulder Creek. This structure and its measurement device must be in place and approved by the water commissioner prior MMM receiving any credit from dewatering unless MMM or the ditch company can show to the satisfaction of the water commissioner that an alternate route was provided to deliver the dewatering water to Boulder Creek. Discharging the dewatering water to Boulder Creek will create an instant dewatering credit and a lagged depletion. The depletions will be lagged using the same AWAS parameters as the evaporation and mining operations depletions. Dewatering is projected to occur at a rate between 52 GPM to 58 GPM, or approximately 7.05 acre-feet to 7.81 acre-feet per month, respectively. Table 2 presents a dewatering schedule that assumes that all of the dewatered water is discharged to the Cottonwood Pond. Actual dewatering volumes will be metered and lagged depletions/credits will be based off of actual use. The Applicant must tract, and measure to the satisfaction of the water commissioner, the amount of water discharged to the Cottonwood Pond, the LCP and the Smith and Emmons Ditch. Replacements This plan provides for three replacement sources that can be used during this plan, which are: water stored in Heaton Reservoir under the junior storage right decreed in case no. 2001CW193, water stored in priority in Heaton Reservoir or bypassed to Boulder Creek