The increased number of residential domiciles and other general development within the region of Darlingtonia State Park have increased the potential for nitrate loading via septic systems and (poorly constructed or aging) exempt wells. Exempt wells allow users to withdraw up to 15,000 gallons per day, an amount that is not regulated or monitored by any agency. Paired with these wells, septic contamination poses a developing threat to the shallow aquifer system and fragile ecosystem of the Darlingtonia californica species. Increasing groundwater vulnerability due to climate change factors, mainly sea-level rise and subsequent salinity intrusion, put local ecosystems and stakeholders at risk of aquifer degradation. How does the increased number of exempt wells and increased nitrate loading from septic tanks paired with exempt wells near Darlingtonia State Park impact the water level and nitrate levels of the shallow aquifer? Do water table and groundwater chemistry fluctuations impact the Darlingtonia californica population within the cedar fen at Darlingtonia State Park? Ongoing groundwater level monitoring is conducted with a pressure transducer installed inside a geotechnical boring on-site. Monthly aquifer chemistry samples are analyzed via anion chromatography (EPA method 300.0) for nitrate and chloride concentrations.
Results/Conclusions
This project commenced in November 2016 and is currently ongoing. A geologic site conceptual model of the Darlingtonia vicinity has revealed that the unconfined aquifer system is within Quaternary sand deposits. A potentiometric surface connecting the aquifer to the nearby lakes and the Pacific Ocean reveal a shallow groundwater table at the Darlingtonia site, a condition necessary for the shallow root system of the Darlingtonia californica. Water level monitoring will likely reveal an aquifer drawdown during the summer months and consistent levels throughout the wet season. Water chemistry results have revealed insignificant levels of nitrate concentrations and chloride concentrations from 10 to 15 ppm. Human-landscape interaction analysis will likely follow the general development trends of the central Oregon Coast. Analysis of historic aerial photographs, public building records, and well drilling logs show that development in the greater Florence area is relatively recent (60 years) and has been on the recent rise. Rural development includes a variety of vacation homes linked to domestic wells and septic systems, recreation sites, commercial tourism services, and industrial/agricultural facilities.