By Sue Danver
The WA Growth Management Act requires a periodic update of Counties’ Comprehensive Plans and related ordinances. For the past two years Thurston County has been updating the Mineral Lands Policy within the Natural Resource Chapter of the Comprehensive Plan. The process is entering its final stages with a possible recommendation by the Planning Commission in July or August and a vote by the County Commissioners sometime in late 2020. Watch for a BHAS alert on recommended options prior to the Planning Commission vote.
Below are issues of concern to BHAS that were brought to the attention of the Thurston County Planning Commission:
Designated Mineral Lands Map Update
Since the 2010 Mineral Lands update, WA now requires each county to create a map of all mineral deposits, which, in Thurston County are aggregate (sand and gravel) and quarry rock (basalt). Thurston County accomplished this task and the map was approved in 2019. 142,170+ acres, a large percentage of county lands (not in jurisdictions), have been designated as Mineral Lands. Prior to this new map, only 5,623 acres had this designation. Mining activity will concentrate in the southern portion of the County, which contains an abundance of high-quality gravel.
Many of these designated lands will not be mined. People who have land that has been designated can ask to remove their property from designated status. Critical areas cannot be mined. But essentially, open space that is greater than five acres and has mineral designation can become a mine once a Special Use Permit (SUP) is approved. The general need for gravel and aggregate usually gives priority to the development of Mineral Lands.
The Planning Commission will next decide on additional options regarding more lands acquiring Mineral Lands designation: What will be the rules for expanding an already existing mine? What criteria must a parcel, without designation, meet to be granted mineral designation?
No planner, mine owner, or citizen knows how much of Thurston County will actually be devoted to mining or the location of new mines. This uncertainty is frustrating, if not frightening. When employing the most generous expansion and non-designated parcel options, up to 210,000 acres could have mineral designation. Currently, setting limits on the amount of land allowed to be mined with mineral designation is prohibited. BHAS hopes that, in the future, such limits can be included in the Comprehensive Plan.
Support for TC’s Hydrologic Code Requirements for Mine Applications
The sand and gravel aquifers in Thurston County provide water to many streams, wetlands, springs, and seeps that are habitat for fish and wildlife in our region. These aquifers also supply high-quality potable water to drinking wells in rural communities, towns, and cities. Altering groundwater conditions through mining changes the amount, timing, and duration of water availability. Such changes can cause harm, in perpetuity.
Unlike most western Washington counties, Thurston County depends solely on its aquifers for water. We have no runoff from high snow-covered mountains to enhance our water supply. Thus, it is critically important to protect the quality and quantity of Thurston County’s aquifer water. Deep mining, a preferred option to ostensibly reduce the number of mines, usually penetrates the aquifer and can interrupt and disturb the hydrogeologic functions. Therefore, BHAS strongly supports the inclusion of pre-permit, hydrogeologic analysis/report requirements in the mineral code section of the Thurston County ordinances.
1,000-Foot Separation Distance to Protect Hydrologic Function.
Since around 2000, Thurston County code has required a 1,000-foot separation distance between parks and mines. In this current Comp Plan update, only 36 public parks and preserves have been selected to have a separation distance. The most important reason for this separation is to maintain the hydrologic functioning of the adjacent park lands.
Areas with gravel substrates are very sensitive. Habitats of many public parks and preserves support uncommon and even threatened or endangered plants and animals. Unique prairies – such as West Rocky Prairie — often with a patchwork of rare types of wetlands, reside on the best gravel in Thurston County. The habitats and the important wildlife species associated with these public parks and preserves, especially prairies, depend on specific seasonal fluctuations in groundwater levels and flows. Altering the timing or extent of seasonal water fluctuations can greatly harm the integrity of the parks and disrupt the narrow range of conditions that animals and plants depend on for their life stages. For example, eggs of the Federally-threatened Oregon Spotted Frog will fail if its wetland home water level varies more than 6” during the egg laying period. The flowering of the Federally-listed wetland plant Howellia will fail with a similar change in water level.
Gravel pit mine evacuation work in Thurston County can substantially affect the underlying aquifers and groundwater levels, flow and quality in adjacent parcels. Analyses of existing and proposed gravel mine lakes in Western Washington show that groundwater levels decline or increase up- or down-gradient from a newly constructed lake whether, or not, a lake-bed clogging layer forms on the mine lake-bed. The magnitude and extent of the hydrologic changes caused by the excavated gravel-mine lakes vary from site to site. In some very sensitive sites, especially down-gradient, impacts to groundwater could reasonably be anticipated to extend substantially farther than 1,000 feet down-gradient from the new gravel pit lake. In other areas, impacts to groundwater up-gradient may also extend more than 1,000 feet from the mine. BHAS recommends that the 1000-foot separation distance between mines and parks and preserves be maintained.
Decreasing the 1,000-foot separation distance also threatens water quality. Fuels and/or other chemicals stored on site are potential contaminants if they spill. The ability to contain or capture spilled chemicals before moving down-gradient and contaminating off-site water resources is compromised as the separation distance is made smaller.
The Comprehensive Plan and the accompanying code language and direction are critical for maintaining our county’s healthy ecosystems and water resources. This current Mineral Lands Policy update process demonstrates how difficult it is to agree on even a modest modification of policy and code. Yes, we need to allow gravel mines because we all use gravel. But we also need to protect our agricultural and recreational lands, as well as secure clean and abundant water for our citizens, farms, and wildlife. The final language of the Comprehensive Plan update will provide direction for the next eight years and probably longer. Let’s be careful in the policy we choose.
