A Validated Method for Pit Lake Water Sampling Using Aerial Drones and Sampling Devices

Abstract

Pit lakes present significant safety risks for boat-based water sampling crews. The Matrice-HydraSleeve method improves the safety of water sampling in pit lakes by eliminating the need for a boat-based sampling crew. The method connects an off-the-shelf unmanned aircraft system, or drone (DJI, Matrice 600) to an off-the-shelf water sampling device (GeoInsight, HydraSleeve). It is capable of collecting 1.75 L water samples from up to 122 m deep and is simpler than previous drone water sampling methods. To validate the method, water samples were collected from similar depths in Dillon Reservoir, Colorado, USA using the Matrice-HydraSleeve method and traditional boat sampling methods using a Van Dorn water sample bottle. Concentrations of Ca, Na, K, HCO 3 , SO 4 , Cl, and Zn showed less than 20% relative percent difference, and concentrations of Cd were within ± the detection limit, meaning variability between samples met the data quality objective for duplicate samples. The method was also used on two occasions to collect eight water samples from the 101 m deep pit lake at the Thompson Creek mine in Idaho, USA including a sample from 92 m deep. Calcium and sodium concentration profiles were nearly identical, indicating little change in water chemistry and providing confidence in the method. In situ profiles of temperature and electrical conductivity collected with a conductivity-temperature-depth probe (YSI, CastAway) suspended below the drone indicated the lake was meromictic during both sampling events. To date, the Matrice-HydraSleeve method has been used at 10 pit lakes in the USA to collect 81 samples. Use of this method at other pit lakes has the potential to improve safety while lowering sampling costs and increasing data acquisition, leading to better pit lake management.

Drone-based water sampling and characterization of three freshwater harmful algal blooms in the United States

“…Benson et al (Benson et al, 2019) used the DrOne Water Sampling SystEm (DOWSE) to collect water and study microorganisms from eight remote Alpine lakes in Austria. Drones have also been used to collect samples from hazardous pit lake environments (Castendyk et al, 2020). Koparan et al (2020) developed adaptive water sampling approaches for bathymetry and turbidity maps at Lake Issaquena, SC.…”

Tracking a Surrogate Hazardous Agent (Rhodamine Dye) in a Coastal Ocean Environment Using In Situ Measurements and Concentration Estimates Derived from Drone Images

“…Third, the red ratio does not incorporate a working knowledge of the vertical dye plume and/or any potential stratification beneath the sea surface (e.g., Lee et al [28] who looked into models of vertical profiles of Chlorophyll from remote sensing of ocean color). Future missions could incorporate sub-surface sampling of the dye using different types of dronebased water sampling devices (e.g., Castendyk et al [29]) coupled with multiple Secchi disk observations (e.g., Lee et al [30]) at the sampling locations, but these additional observations were beyond the scope of resources and capabilities available to the present study. Consequently, dye estimates based on red ratios derived from our drone images may in fact include some dye beneath the water surface.…”

A Novel Automatic Water Autosampler Operated From UAVs for Determining Dissolved Trace Elements

“…The application of UAVs is suitable for a multidisciplinary studies approach, since they can be applied to a wide range of fields, using different sensors and devices (Park & Choi, 2020, and the references therein). Several new technologies of water sampling tools mounted on UAVs have been designed and successfully applied in different conditions; for example, wetland ecosystems (Schwarzbach et al, 2014), pit lakes (Castendyk et al, 2020) and freshwater (Koparan et al, 2020). Remote water samplers have been used for the determination of a wide range of chemical and physical parameters; for example, temperature, pH, alkalinity, dissolved oxygen, major ions, such as sulfate, chloride, calcium and manganese (Detweiler et al, 2015;Ore & Elbaun, 2015;Castendyk et al, 2020).…”

“…Several new technologies of water sampling tools mounted on UAVs have been designed and successfully applied in different conditions; for example, wetland ecosystems (Schwarzbach et al, 2014), pit lakes (Castendyk et al, 2020) and freshwater (Koparan et al, 2020). Remote water samplers have been used for the determination of a wide range of chemical and physical parameters; for example, temperature, pH, alkalinity, dissolved oxygen, major ions, such as sulfate, chloride, calcium and manganese (Detweiler et al, 2015;Ore & Elbaun, 2015;Castendyk et al, 2020). However, to the best of our knowledge none of these devices have been designed exclusively for the determination of dissolved trace elements in marine environments.…”