It appears that a large percentage of Silver Star Mountain Resort's sewage effluent is emerging in springs almost 12 kilometers from the sewage lagoons, contaminating Coldstream Creek and the Coldstream Community Aquifer. Since the high-nitrate springs emerge in an agricultural area, the Ministry of Environment, Greater Vernon Water, and Interior Health have assumed, despite evidence to the contrary, that the high nitrate levels in the Coldstream Community Aquifer are due solely to agricultural inputs.
Antwerp Spring #1 aquifer has a chronic problem with high nitrate levels, which rise dramatically every ski season. Springs emerging north of Highway 6 and east of School Road contain high levels of nitrates, which most likely originate in the Silver Star sewage lagoons. These springs contribute to high nitrate levels in the creek and in the unconfined aquifer.
Silver Star effluent emerges in springs north of Highway 6 and west of Noble Canyon, where it flows through culverts under the highway and into Coldstream Creek, only a few hundred metres upstream from the Antwerp Springs pumphouse. When the water table is low (mid-summer to late winter), most of this high-nitrate spring water sinks into the unconfined community aquifer, rather than flowing down the creek. The red algae is likely indicative of high nitrate levels in the creek.
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Greater Vernon Water is deeply concerned about the high nitrate levels in the Coldstream Community Aquifer, and therefore monitors the water quality weekly. The above graph clearly demonstrates how nitrate levels in the community aquifer spike during the ski season, almost in lockstep with nitrate levels and sewage lagoon depths at Silver Star Mountain Resort, over 12 kilometers away. Agricultural land uses would not cause the dramatic spike in nitrate levels during the winter months.
This graph of historical nitrate levels in Antwerp Springs #1 aquifer clearly shows how nitrate levels rise every winter during the ski season. Antwerp #2, which is a much deeper, confined aquifer, appears to be largely unaffected by the Silver Star effluent.
The graph shown above is from Silverhawk Utilities' 2008 Annual Report. Total nitrogen levels in the seepwater streams (designated SW3 and SW4) near the lagoons provide a good indication of effluent quality being discharged to the fractured carbonate bedrock aquifer on Silver Star Mountain. Nitrate and total nitrogen levels in the wastewater rise dramatically mid-winter, due to near-freezing effluent temperatures and short cycle times through the sewage treatment plant.
The aerial photo above shows the most likely scenario of how Silver Star wastewater enters Coldstream Creek and the Antwerp Springs #1 unconfined aquifer. Emerging from a carbonate bedding plane, it appears that a small percentage of the effluent may be saturating the slide area above Noble Canyon, with the majority making its way into Coldstream Creek between Hill Drive and School Road. Solution channels in the limestone may act as the geological equivalent of a pipeline, resulting in short contaminant transport times. Though no large caves have been found to date on Silver Star Mountain, the area around Noble Canyon contains many karst features.
The map ahown above depicts the catchment area for Antwerp Springs #1 aquifer. The Silver Star sewage lagoons are perched on the divide between the Coldstream Creek and Vance Creek drainages, approximately 12 kilometers from Antwerp Springs. When the lagoons were first constructed, it was assumed that all of the effluent would make its way into the Vance Creek drainage; however, it is now apparent that the majority seeps down through the bedrock to limestone bedding planes, where it then heads south along solution channels, finally emerging in springs in the Coldstream Valley.
Simplified cross-section demonstrates how Silver Star effluent could make its way to the Coldstream valley along solution channels in fractured carbonate bedrock. It is possible that minimal dilution of the effluent occurs, since most precipitation contributes very little to the carbonate aquifer recharge, instead running off on the surface or being lost through evapotranspiration.
Water Quality Study Identifies Nitrate Problem in Coldstream Creek Near School Road
The 2008-2009 Coldstream Creek Water Quality Monitoring Report, prepared by the Ministry of Environment, Environmental Protection Division, clearly identified a nitrate contamination source along the 2.7 kilometer reach of Coldstream Creek between Noble Canyon and School Road, in Lavington. Unfortunately, funding was not available to investigate the issue further. Fortunately, members of the Citizens' Coalition to Save Silver Star Provincial Park looked into the matter, walking the creekbed for the entire 2.7 kilometer reach, thus identifying springs north of Highway 6 as the source of the nitrate contamination. The bar graph below, extracted from the Monitoring Report, clearly shows the spike in nitrate levels between Noble Canyon and School Road.
The bar graph above clearly shows nitrate levels spiking between Noble Canyon and School Road on March 31st and April 7th, 2009. Due to lack of funding, the Ministry of Environment did not investigate further. Instead, they concluded in their report that the spike in nitrate levels was simply due to agricultural influences.
This limestone bluff on the east side of Noble Canyon, and the area surrounding it, contains many karst features, including solution channels, proto-caves, and limestone pillars. Karst topography can often provide ideal conditions for rapid contaminant transport through carbonate bedrock via solution channels and bedding planes.
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