2011-04-26_REVISION - M1978210 (3)

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EXHIBIT G - Water Information Water Resources The site lies within the Cache La Poudre River FEMA-designated floodplain. The existing East and West Geisert ponds lie within the floodway. The Cache La Poudre River channel lies immediately to the south of the existing Geisert ponds proposed for slurry wall installation. There are existing surface water impoundments at the Geisert site (See Exhibit C). The gravel pit operates under a Substitute Supply Plan with the State Engineer's Office. The SEO permit number for the gravel pit well is 50425- F. There are surface water impoundments directly north of the Geisert East and West pits proposed for slurry wall installation. • The 26.57 acre "L-shaped" pond (Area B) is a mitigation wetland constructed from a mined out area by Weld County at the direction of the U.S. Army Corps of Engineers. • The adjacent Hiner gravel pit, still under DRMS permit #M-1977-151 is privately owned and is currently utilized as a recreational "ski" lake. • Water for dust control operations conducted by Weld County at the Geisert site has been obtained from a County-owned well located at the west end of the mining permit area. This Geisert dust control well is covered under a Substitute Supply Plan with the State Engineer's Office, conversion of the SSP to a permanent augmentation plan through the Water Court (Water Court Case Number 2004CW359) is in process. SEO Well Permit 50426-F has been issued for the dust control well. • At the east end on the Geisert site, there is a return "slough" connecting the Area B mitigation wetland pond to the Cache La Poudre River. Groundwater The East and West Geisert pits intersect groundwater in their currently un-lined condition. By definition, the North Greeley area groundwater piezometric surface intersects the water surface of the Cache La Poudre River. Regionally, on both sides of the river, the groundwater gradient in the Poudre River valley slopes easterly toward the confluence of the Poudre and South Platte Rivers. South of the Poudre River, the groundwater gradient slopes generally towards the river (northward). Due to the presence of the Poudre River channel, groundwater levels and gradients south of the river will not be affected by any groundwater changes on the north side of the river. North of the Poudre River, the groundwater gradient slopes generally towards the river (southward). In the vicinity of the Geisert site, however, the groundwater gradient is interrupted by the presence of the Hiner gravel pit lakes and the Geisert mitigation wetland. The Hiner gravel pits adjacent to the East and West Geisert pits intersect ground water and are currently in communication through the pit walls. The mitigation wetland (Area B) at the Geisert site will not have a slurry wall lining. The location of the wetland and its direct down-gradient connection to the Poudre River via the existing slough will allow equalization of water levels between the Hiner ponds, the wetland, and the Poudre River. The proposed lining of the East and West Geisert pits (Area C) will not have a significant groundwater "mounding" impact since the adjacent open-surface pit lakes and the river itself will prevent mounding. With the East and West Geisert pits in the un-lined condition, river water infiltrates the river bed and banks and flows through the Geisert pit walls into the pits. Installation of the Geisert slurry walls will reduce river losses to the pits. M:\DAVE B\Geisert Pit\DRMS Permit Amendment\Geisert Amendment Application & Exhibits Revised 4-21-11.docx