Balloon Platforms for Remote Sensing of Water Quality in Mixing Zones

MixZon, Inc., hypothesizes that lightweight infrared (IR) and video cameras mounted on an unmanned tethered helium balloon accessible via a wireless network can remotely sense water quality at site scales. MixZon will demonstrate the technical feasibility of a ground-based network to monitor and control balloon-mounted, IP-enabled wireless IR and video cameras for measurement of the spatial distribution of surface water temperature within the mixing zone. The mixing zone is the area where the initial dilution of a point source discharge occurs. This technology has immediate application to provide geospatial data for regulatory management and simulation model development and validation. Mixing zones are an important component of the National Pollutant Discharge Elimination System (NPDES) point-source discharge permitting process within total maximum daily load (TMDL) water quality management programs. MixZon will focus on mixing zones in rivers, where vertical mixing of point-source discharges is rapid and may be exhibited downstream for long distances, resulting in full lateral mixing. MixZon will integrate existing technology to demonstrate the rapid deployment of small balloon-mounted detectors to monitor mixing zones of industrial discharges. A balloon has a number of advantages over existing platforms for remote sensing of water quality. Existing platforms for remote sensing of water temperature at the site have limited availability, high costs, and long lead times to schedule deployment. The cost of a balloon platform is likely to be one-thirteenth to one-tenth the cost of the fixed-wing and helicopter alternatives, respectively. In addition, a low-cost balloon platform could be deployed on short notice by one to two people with minimal operator training and would be suitable for monitoring at fixed locations for longer time periods than is practical for current airborne sensors. Although water temperature is an important TMDL parameter in itself, temperature often can be used as a “tracer” to indicate the dilution and spatial distribution of other important TMDL water quality parameters, such as sediment and coliform, which may occur within a mixing zone. Although MixZon will focus only on detecting temperature as a water quality parameter, there is the potential to monitor the fate and transport of other discharge constituents, including shoreline recreational exposure to pathogens from wastewater discharges, determination of the spatial extent of contaminated sediment deposits from mining operations, the impact of contaminated groundwater interaction within groundwater/surface recharge zones, and analysis of thermal refugia habitat for endangered species management.