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Memorandum to Harvey W. Curtis <br />June 14, 2006 <br />Page 6 <br />minimized by measures including, but not limited to, compliance with applicable water laws and <br />regulations governing injury to existing water rights and compliance with applicable federal and <br />Colorado water quality laws and regulations. <br />Discussion: A wetland survey for the northernmost 322 acres of the 59.5 acre site was <br />included as part of Exhibit I (Soils Information). (It is not known whether the southern 27.3 acres <br />were surveyed.) AB Environmental Consulting, Inc., conducted the survey on August 1, 2005. It <br />found a jurisdictional wetland azea on the northeast corner of the property of approximately 0.69 <br />acres in area. It found the wetland has high quality plant diversity. The hydric soIls were saturated <br />to within 3 inches of the surface, with up to 12 inches of standing water in places. AB <br />Environmental noted the wetlands are supported by water flowing on the surface of the site in a wide <br />shallow channel. The aerial photograph included with AB Environmental'srepnrt shows the wide <br />shallow channel draining the wetland, but does not show the upstream ditch/channel that feeds it. <br />The upstream ditch/channel can be seen in Objectors' Exhibit 12, which shows surface water on an <br />aerial photograph taken October 12, 1999. <br />This information is supported by similaz findings on the part of Pazk County. As part of the <br />Counry's review for the rezoning of the subject property, County Planning Department staff <br />commented that the project has the potential to violate the County's Strategic Master Plan, which <br />includes preserving and enhancing critical natural areas including wildlife habitat and wetlands. <br />Staff noted that the northeast comer of the property has wetlands and a "Very High" wildlife <br />potential. <br />While the 0.69 acre wetland itself was included on Exhibit C, the channel draining the <br />wetland and the ditch/channel upstream of the wetland were not included. (Exhibit C should also be <br />modified to reflect the County's Permit requirement that no mining acfivity may occur within 100 <br />feet of the delineated wetlands.) Further, the application did not address the potential impacts to the <br />hydrologic balance in the vicinity of this important wetland. <br />Even though, as noted in Exhibit I, the wetland is sepazated from the targeted gravel reserves <br />by an old railroad grade, hydrologic impacts to the wetland could still occur, The project could <br />potentially affect the surface wetland as well as the upstream and downstream channels and ditches. <br />It is likely that the mining activities could cause the surface wetland to drain through the highly <br />porous alluvium into the proposed gravel pit as it is mined to its ultimate depth. This could also <br />affect the downstream channel that currently drains the wetland. The applicant has not evaluated <br />these potential impacts. <br />Conclusions: MLRB should require a ground water monitoring program to document the <br />actual ground water levels across the site and acquire data to assess the likely impacts to the <br />prevailing hydrologic balance. MLRB should require that the existing three monitoring holes be <br />supplemented by at least two additional wells. (See Objectors' Exhibit 11). Although the applicant <br />has already drilled three monitoring wells on the site, one of the monitoring wells was located more <br />than 800 feet south and another was located more than 1300 feet south of where the applicant <br />indicated they would be located in its Response to the Second Adequacy Review. (See well <br />completion reports attacleed to applicant's Response to the Third Adequacy Review). There are no <br />current monitoring wells at the north end of the site. One of the new monitoring wells should be <br />located neaz the northeast corner of the site, to document water levels and impacts in the vicinity of <br />the wetland. The other new monitoring well should be in the northwest portion of the site, near the <br />LEONARD RICE ENGINEERS. INC. <br />