Section GE 3.01 of the Boulder County Comprehensive Plan [PDF] reads, “The county shall render land use decisions consistent with the preservation or improvement of groundwater quality as well as the conservation of groundwater supplies.” Residents in the area consider well water precious, and we reject water delivery by trucks or other means as a reasonable alternative for its permanent loss due to mining operations. Our page on the effects of gravel mining on groundwater addresses specifically how residents’ wells may be seriously impacted by the proposed mining operation near Hygiene. Previous surface mining in the valley lowered the water table, and permanently dried up an artesian spring and well on a neighboring property. Aside from affecting the supply of well water, there is also a risk that exposing the top of the aquifer may cause contamination to our groundwater. One example is that a spill could contaminate the underground water without the overlaying soil protection to filter the chemicals or contaminants. This is described in a 2011 study for the Municipal District of Peace in Alberta, Canada [PDF] (16).
2013 flood’s effects and need for repairs
Our Water page includes a photo of a private pond in the vicinity of the planned mining operation, which illustrates that the water table has not recovered following the 2013 flood. Restoration of the water table and flood damage need to be repaired prior to permitting additional mining activities that may add insult to injury.
The 2014 St. Vrain Creek Watershed Master Plan [PDF] contains recommendations for restoration of the area, which is designated as Reach 3. It states, “Although the adjacent floodplain has been historically connected to the channel, sand and gravel mining operations have altered the natural floodplain function for a majority of this reach” (7-8). As noted on our environment overview page, this plan describes how the large split flow paths that formed during the flood resulted in flooding damage downstream in Longmont, outside of the 100-year floodplain. The 30% Design Report, St. Vrain Creek Restoration, Highway 36 to Crane Hollow Road [PDF] report (prepared for Boulder County Parks and Open Space) addresses the specific repairs for this reach in detail. It notes, “A comprehensive restoration for the entire reach is necessary, incorporating the individual restoration efforts of individual projects through the reach, to provide a single holistic restoration approach for the entire reach” (2). Regarding mining areas, the watershed plan asserts that any flood repair work should be coordinated with mining activities to promote flood risk reduction and habitat enhancement (7-9). Is this happening, and if so, what form is this coordination taking?
As mentioned above, the BCCP Geologic Hazard and Constraint Areas Map illustrates that the proposed mining is slated to occur in a “Geologic Hazard Area.”
The Boulder County Comprehensive Plan (BCCP) addresses various land use issues, and includes information relevant to this proposed mining project. Links to the numerous maps in the plan are also provided on the BCCP website. I’d like to remind the Director that The BCCP Geologic Hazard and Constraint Areas Map designates the majority of the proposed mining area as a Moderate Hazard Area. “Geologic Hazard Area,” with a “Moderate” risk of flooding. The Geology Element of the plan states, “Moderate Hazard Area shall mean that area, or those areas, as shown on the Geologic Hazards and Constraint Areas Map where geologic conditions are such that significant geotechnical problems exist and there is provisional risk related to intensive land uses” (Geology [GE] – Page 1). Notably, GE 1.02 states: “The county shall discourage intensive uses in Moderate Hazard Areas.”