Autonomous Water Sampling with the RDST Delivery Drone
The A2Z Drone Delivery team recently conducted trials of drone-borne water sample collection in Manhattan Beach, CA. The water analysts were looking to collect samples of river runoff from rain storms to evaluate the makeup of storm drain outflow to the sea. The samples needed to be collected from about 1,000 feet offshore. Additionally, they needed to be conducted quickly, within 48 hours of rain events, so rapid deployment was imperative to the success of the operation.
Traditionally, analysts would be required to load out in boats to find the edge of the rain water plume flowing out of the river delta. Then they would lower sample collection buckets on a line to retrieve the samples. This process required a great deal of equipment and manpower, and took valuable time to collect.
Drone Water Sampling Trials
In this simple proof-of-concept, the A2Z team demonstrated that our RDST medium-range off-the-shelf cargo drone, and its integrated RDS2 drone winch, could easily streamline the sample collection operation. The UAS delivery platform was launched from a nearby parking lot and flew to the prescribed offshore distance. Once on site, the downward-facing camera was able to identify the edge of the rainwater plume, and lowered its collection vessel. Able to retrieve payloads up to 5 kg while maintaining a safe hover, the RDST delivery drone with its onboard RDS2 delivery winch, easily winched up the 2.5 gallons of water. The RDST returned to the operation base, and gently lowered the open water vessel. The delivery drone was kept at a sufficient altitude so the prop wash would not kick up sand and debris that could contaminate the open sample. Round trip, the RDST was able to collect each sample in just about eight minutes, a massive time savings from manned boat deployments.
Why Collect Water Samples by Drone
Conducting scientific water sampling in traditional ways would usually call for large teams to deploy to a shoreline or reservoir. Launching boats, or requiring multiple trips, to accurately sample the entire body of water is an expensive proposition, both in equipment investment and manpower. Leveraging drone technology to streamline these sample efforts holds some real benefits for analysts, including:
Operational Efficiency – A single aerial water-sampling drone can conduct the same round-trip mission as staff in an inflatable boat in just minutes. Minimizing the needed manpower translates to real savings in operational budgets. Drones can also cover vast areas in far less time than staff in boats, allowing a team of one or two people to sample an entire reservoir in a single day.
Rapid Autonomous Deployment – With a water-sampling drone, the pilot simply programs multiple sampling targets into the A2Z Ground Control Station. The entire user interface is managed by inserting waypoint locations on the generated map, or inputting pre-determined GPS coordinates. With the touch of the “start mission” button, the drone will autonomously fly to the waypoint, collect the sample, and return to the origination point. On-shore staff simply remove the sample, replace the collector, and tap the next waypoint for the operation to be repeated.
Team Safety – Relying on a drone for water sample collection keeps all operators and sample collectors safely on shore with no need for the team to be hanging over the side of small boats. Additionally, if potential harmful compounds might be present in the reservoir, the sampling staff is not subjected to long durations on the water.
Avoid Boats Churning Up Sediment – Even the small outboard motors on inflatable boats can churn up sediment and debris on the floor of a reservoir. With a drone that collects water samples, especially from altitude, sediment cannot contaminate samples.
Benefits of Tethered Retrieval of Water Samples
While the benefits of leveraging drone technology for collecting water samples are quite alluring, conducting the missions with a flight platform equipped with a UAS winch, delivers even further benefits. Some of these added advantages include:
Maintain Visual-Line-of-Sight – Given the current regulatory environment in the US, all drone flights must be conducted within visual-line-of-sight, meaning the operator cannot lose sight of the drone at any time. Whether you are conducting offshore water sampling with drones, or looking to collect samples from an inland reservoir, keeping the drone at a high hover (up to 30 meters above ground level with our RDST) ensures longer distance mission reach with line-of-sight.
Prevent Sample Contamination in Open Collectors – For analysts leveraging open-top collection containers, preventing contamination of those samples upon the drone’s return trip is imperative. While there is minimal contamination potential during straight and level flight, when the drone needs to deposit the sample back at the operations center, prop wash could kick up dust and debris. By slowly lowering open container samples to the ground from altitude on a drone tether, this likelihood is minimized.
Control Sample Depth with the Tether – When collecting water samples at specific depths, water sampling drones with fixed collection umbilicals are required to hover closer to the water to fill their canisters from the target depths. Our RDST with its onboard RDS2 drone winch uses a single-point high definition lidar to accurately chart its altitude. The UAS winch can then be extended beyond the surface of the water to precise depths. The RDS2 drone winch references how much line is extended with the lidar altitude reading to deduce the depth of the sample.
Mitigate Disturbances to Surrounding Wildlife – A convoy of boat trailers, trucks and a large team can be quite disturbing to the environment, both wildlife and vegetation. A tethered delivery drone, though, quickly flies over all of the local flora and fauna for the least disturbance possible.
Drone Tether Can Be Collection Bottle Agnostic – With the addition of a simple servo release for the sampling bottle messenger (the weight that drops to activate the bottle closing mechanism), you can leverage any type of collection bottle including the Niskin bottle, Ruttner bottle, or Van Dorn bottle.
Automate Your Water Sampling Today
If you are looking to implement drone borne water sampling for your municipal water treatment system, environmental monitoring service, etc. please contact our team today. We can identify the ideal A2Z Drone Delivery platform for your specific water sampling deployments, that will help keep your staff safer, streamline your operations, and ensure more accurate sample data.
