Water Is A Limited Resource Environmental Sciences Essay

Water is a limited resource whose quantities and quality are declining for an ever increasing world population. In the future this scarce resource needs to be managed better and efficiently. Water is the main theme of my research because it is undoubtedly the most critical and vulnerable resource to humans and entire ecosystems. In order to understand the physical and biogeochemical processes that affect this resource, I have focused current research in water, agriculture and forest resources. The primary focus of my research is to improve our understanding of the hydrologic and terrestrial processes regulating the quality and quantity of water in watersheds, so better environmental policy and management strategies that protect water, soil and other natural resources can be developed. My research addresses both managed and natural systems, considers processes at small to large river watershed scale, and uses combined effort of field monitoring, modeling and application of results to real world problems. It is my view that only by integrating across scale and between disciplines we will ever be able to understand these interactions and their potential implications at different scales. Building on my expertise, past and current research experiences, I have three broad and somewhat overlapping research themes. They are: 1. Land use change and management impacts on water quality and quantity, 2. Impact of climate on hydrologic and terrestrial processes, and 3. Bridging basic research and modeling efforts for effective management and policy decisions.

Impact of land use on water quality: Many of my research projects have characterized the relationships between land use management, patterns, and sources of runoff, sediment, and nutrients in the landscape and used this information to predict stream water quality/quantity. For example, in my doctoral dissertation research I assessed the impact of land use and management practices on water quality/quantity for a drinking water supplying watershed and lake. To do this I combined stream monitoring, and distributed watershed modeling. My study site included both agricultural areas that have best management practices already implemented and forested areas with minimal human impacts. Assessment of the impacts of BMPs on water quality is challenging because implementation of whole-farm management programs has been on-going in the watershed; farms where BMPs had not been implemented were not available for monitoring in the current study. Consequently, the classic paired watershed approach involving comparison of treated vs. control subwatersheds was not possible. Minimal divergence of water quality between watersheds dominated by forest land use and those dominated by agricultural land use provided indirect evidence of agricultural BMP effectiveness. Individual cell contributions to total yields of water, sediment and nutrients at the outlet were calculated, facilitating identification of specific cells contributing disproportionately to non-point source pollutant inputs. Effectively, those are the areas where management intervention may provide the greatest impacts on maintenance and improvement of water quality.

This type of comprehensive watershed scale research not only allows us to quantify the effects of management practices on surface water quality, which are to be significant, but gives us clearer insight into controlling processes and their distribution in a watershed. I recently used a similar modeling study approach to quantify snowpack distribution in New York City (NYC) water supply watershed, as snow is an important component of the water resources of New York State and the watersheds and reservoirs of NYC water supply (Pradhanang et al, 2011, Hydrological Processes). I will continue to expand this type of research to larger systems by incorporating geospatial information and remote sensing into both the field and modeling components of my research. My research results have shown that when studying at the large scale response, it is important to consider small areas of a landscape or spatially distinct zones. One challenge that will be critical in future work will be determining how to effectively monitor and model small scale processes, particularly with respect to biogeochemical processes, while also applying small scale processes to larger systems.

Impact of climate on hydrologic and terrestrial processes: My ongoing research in this area focuses largely on determining relationships among biogeochemical processes, hydrology, and the influence of climate in both the US and Nepal. Since 2009 I have been involved with researchers from New York City Dept. of Environmental Protection tasked with assessing effectiveness of land and watershed management practices to ensure abundant, clean water in the New York City Watersheds. In addition to land use impacts on water quality and quantity, another major concern in the watershed is the influence of climate change on terrestrial biogeochemistry, water quality, and water quantity. One of my roles has been to develop and test basin scale hydrologic models designed to capture the variable source area (VSA) hydrology that dominates the region, and that will provide accurate estimates of both water quality and quantity. As part of this effort I have updated, modified, and applied model that is currently being used, the Soil and Water Assessment Tool (SWAT) which were not originally designed to capture the complexity inherent in saturation excess runoff process. I used streamflow predictions from SWAT-WB (modified version) to assess effects of climate change and potential changes in hydrologic indicators (Pradhanang et al., JAWRA in revision). Currently, I am working towards simulating nutrients in agriculture dominated watershed. Rising atmospheric CO2 concentration, higher temperatures, changes in precipitation pattern, duration and frequency will have significant effects on vegetation and crop growth affecting food security. I have applied watershed and ecosystem model in order to effectively understand potential effects. I have recently worked with a graduate student at City College of New York to couple watershed models distributed snow model and also with radar and other remote-sensing techniques. My future research in this area will build and expand on identifying and quantifying hydrologic processes controlling biogeochemical fluxes in the landscape, especially those most relevant to anticipated environmental changes associated with climate change.

I also plan on expanding my work in places like Nepal where the potential impact of global climate change on soil and water resources could be devastating and where resources for solving the resulting problems are least available. Of particular concern is resultant impact on agricultural productivity due to changes in hydrology, either climate driven or as a result of manipulations to hydrology (e.g., irrigation), or soil quality. Thus, a better understanding of the hydrological and biogeochemical systems in these areas and their linkages to climate are critical to improving the quality of life around the globe.

3. Bridging basic research and modeling to management and policy: Work that interfaces directly with planners, managers, land owners, and policy makers is some of the most rewarding of my (short) career. For instance, results from Ph.D. research are currently being considered in New York to identify source areas and effectively apply management plans in identified sources. My on-going research in New York is a good example in which I have worked directly with New York City Dept. of Environmental Protection scientists and managers to develop and assess water quality protection strategies for the New York City water supply. I am also involved with USAID as well as federal, regional, and local community leaders in a project entitled “adaptation of livestock smallholders to climate change in Nepal”, a project assessing the historic, current, and future of livestock resources in the Gandaki River Basin (GRB), Nepal. This project is truly interdisciplinary, bridging the fields of hydrology, engineering, agronomy, soils, economics, social science, and climatology as well as watershed stakeholders and government officials in a dynamic and rapidly changing region of the world. Nepal holds vast potential (both beneficial and dire) to influence global issues such as human induced climate change, economics, and population pressure. I find it exciting to work on a project with potential global impact. My role involves developing models of hydrology and crop growth to determine potential effect of climate change on streamflow and crop yield in GRB that can have direct impact on livestock water management and feed and fodder availability. The model integrates our current knowledge of spatial and biogeochemical processes and a large amount of remotely sensed information (TRMM derived rainfall, ensemble forecasts, Landsat imagery, etc). In fact, remote sensing platforms are essential for large scale modeling and analysis of climate and terrestrial systems, especially for parts of the world with little reliable ground monitoring. The implications of this project are far reaching and will inform governments and watershed stakeholders on the consequence of factors both within and beyond their control. Moving forward, I would like to keep these types of linkages between my research and environmental managers.