In recent years, the Great Lakes water basin has suffered from nonpoint source pollution (NPS) causing excessive eutrophication in the waterways vital to the health and agriculture of the surrounding communities. It is a challenge and area of concern to protect and maintain these important freshwater reserves to ensure their quality and health for generations to come.
The runoff of fertilizers and pesticides from agricultural areas resulting in excessive nutrient inputs to adjacent watersheds and lakes – known as eutrophication – is recognized as one of the leading causes of non-point source pollution in waterways across North America. NPS, unlike clearly identifiable and treatable point source pollutants, are dynamic and result from a wide range of uncontrolled activity along the effected watersheds. The importance and industrial growth of agriculture across many of North Americas watersheds has resulted in increased agricultural runoff and eutrophication, affecting fish populations, aquatic plants and entire ecosystems. The difficulty in characterizing NPS pollution is due to their tendency to diffuse and discharge in sporadic events – making it very difficult to track and pinpoint the pollutant origin or event.
The monitoring and mapping of problem areas along large watersheds and lakes poses a serious problem for all stakeholders involved. “Most traditional water surveillance systems are retrospective and reactive. A robust and proactive water quality monitoring system is needed to provide early warning of contamination outbreaks”. The lack of even distribution across tributaries, absence of continuous monitoring at major drainage sites and limited monitoring of shorelines are just some of the problems associated with the inadequate water quality monitoring along the Great Lakes.
By gathering and analyzing remotely sensed data, farmers and key stakeholders can track and monitor NPS pollutants along coastlines and detect early signs of contaminants entering the waterways. The use of UAV as a mounting platform for some of these unique and beneficial remote sensing systems allows for programming with pre-determined flight paths for image acquisition and data retention over vast areas of land and water. A key area that has been exploited by UAV applications is the monitoring and mapping of biomass and the health of vegetation and pollutant eutrophication along wetlands, coastlines, and agricultural land masses. The use of multispectral and hyperspectral imagers allows monitoring and tracking of harmful algal blooms and patterns in pollutants and phosphorous runoff from farmland to adjacent watersheds.
The use of remote sensors on UAV platforms provides a unique solution that is accurate, flexible, cheap, and one of the fastest ways to detect and predict eutrophication and algal blooms in important watersheds and lakes. The real time tracking and monitoring of land and areas adjacent to bodies of water helps in determining the root cause of these NPS pollutants by tracing them back to geographical locations. By deploying a UAV system near coastlines and areas susceptible to agricultural runoff, remotely sensed imagery can be captured to determine specific locations and extent of the pollution. From these images the polluted areas can be assessed and mapped with a formulated plan to reduce and mitigate the NPS pollutants at the source that are entering and polluting the sensitive waterways.