Climate Impacts on Sustainable Natural Resource Management. Группа авторов

Figure 2.2 Applications of geospatial techniques for forest resource assessment and mapping.

      2.2.2 Water Resource Management

      Water is an essential natural resource for human existence. Over the years freshwater availability for human utilization has been declining, whereas the growing population demand increases. Therefore, there is a pressing need to monitor this vital resource and better understand its sustainable use approach. Water, soil, and vegetation are vital natural resources and hence should be managed effectively and simultaneously. A watershed is the smallest planning unit that efficiently represents a continuum of these three resources. This knowledge can help develop effective water management strategies, and it can be of crucial importance for regions with limited water availability.

GIS renders the technology for delineating land use pattern, land resource assessment, irrigation water management, flood management, and monitoring the environmental impact of watershed projects. It is also an excellent tool for delineating hydro‐morphological units in problematic areas for selecting suitable sites for water harvesting structures. Geospatial techniques have emerged as indispensable tools for mapping and planning natural resources (Mahajan and Panwar 2005; Vittala et al. 2008; Bryan et al. 2011; Burkhard et al. 2012). These techniques play a significant role in various fields of watershed aspects, such as estimating evapotranspiration (ET) (Bashir et al. 2008; Elhag et al. 2011), runoff modeling (Shrivastava et al. 2004; López‐Vicente et al. 2013), soil erosion (Vemu and Pinnamaneni 2011; Esteves et al. 2012), flood‐management (Park and Hur 2012; Steinfeld and Kingsford 2013), and irrigation management (Georgoussis et al. 2009; Saidi et al. 2009). Figures 2.3 and 2.4 show flow diagrams for geospatial technology's role in assessing groundwater potential and its role in watershed prioritization, respectively.

Figure 2.3 Representation of multiple spatial layers that can be developed with the assistance of geospatial technology to assess groundwater potential. Based on Georgoussis et al. (2009).

      2.2.3 Water Quality Monitoring

      Water quality monitoring is required to be managed on a regular basis for human consumption purposes. Water quality is currently analyzed in the laboratory or through in‐situ measurements. Although these measurements are accurate, they miss the spatial and temporal components needed for water body management. These are also expensive and time‐consuming procedures that cannot satisfy the monitoring needs on a large scale. Remote sensing technology can be employed for monitoring different water quality parameters (i.e. temperature, turbidity, and chlorophyll content). Thermal and optical sensors can retrieve spatial and temporal information required to monitor water quality and develop management practices. Remote sensing is also used to measure suspended sediments and chlorophyll concentrations spatiotemporally based on empirical relationships with radiance or reflectance (Ritchie and Cooper 1991; Ritchie et al. 1994).

Figure 2.4 Development of thematic maps and their integration for the prioritization of activities in a watershed using GIS. Based on Georgoussis et al. (2009).

      2.2.4 Agriculture

The plants interact with the sunlight differently based on the observed wavelengths. The incident solar radiation can either be transmitted, absorbed, or reflected. The pattern of transmittance, reflectance and absorbed part of electromagnetic (EM) radiation provides essential insight to acquire information about plant physical and physiological status. Such as the absorbance bands of EM radiation (i.e. short wave infrared – SWIR 1 near 1.5 μ and short wave infrared‐ SWIR 2 near 2.5 μm) suggests the moisture availability in plants and vegetated landscapes. The health of forests or the photosynthesis activity by chlorophyll can be detected by analyzing the photosynthetic active radiation (PAR) range of EM waves where utilization of PAR is manifested as low reflectance of PAR in 0.6–0.7 μm range. Relating to their structural and biomass properties, leaves exhibit high reflectance and transmission in the near‐infrared spectral region (0.7–1.3 μm) (Tucker 1979; Avery and Berlin 1992). The structure of leaf area and plant canopy is also generally related to the reflectance patterns (Rautiainen and Stenberg 2005; Disney et al. 2006) which play a key role in growth monitoring. The absorption of radiation in the shortwave infrared region (1.3–2.5 μm), is mostly dominated by water and some biochemical components present in leaves. The phenological stages of plants and their interaction with different environmental aspects can be translated into unique signal patterns. These patterns or changes in electromagnetic radiation reflectance can then be interpreted and monitored using satellite data (Sharp et al. 1985; Blazquez and Edwards 1986; Curran et al. 1990; Miller et al. 1990; Pen Uelas et al. 1995; Kokaly 2001; Aparicio et al. 2002; Steddom et al. 2005; Disney et al. 2006; Guerif et al. 2007; Chen et al. 2010). The Chlorophyll content in vegetation is linked to the photosynthesis process and can be detected using the remotely sensed signature of selected EM wavelengths. Remote sensing signatures can further be linked to the various levels of stresses a plant may be facing. Thus remote sensing serves as a useful tool for monitoring the global health of vegetation (Gitelson and Merzlyak 1996) to suggest for water content and biomass of a vegetated landscape. This exemplifies the use of spectral signature in monitoring vegetation and its different parameters such as leaf area index, growing season, water stress, chlorophyll content, leaf structure, etc.

Figure 2.5 Applications of geospatial techniques for crop monitoring and management.

Precision agriculture is a site‐specific crop management prescriptions relying on information that can be measured using remote sensing for different crops across varying spatial and temporal scales. This system utilizes the power of modern technologies and information sources, including remote sensing, GIS, and GPS (Figure 2.5). Remote sensing supplements cost‐effective data for developing plans for precision agriculture. At the same time, the geographical information system provides a robust and flexible environment for the storage, processing, manipulation, analysis, and displaying of multiple spatial layers that can be used for the monitoring of agriculture and formulating a decision support system. Satellite imagery can be used for mapping discrete land cover and land use and for estimating other parameters of vegetation using spectral signatures (Steininger 1996).

      Agriculture is the primary consumer of water, utilizing more than 70% of the global freshwater. Therefore, the role of irrigation water plays a significant in increasing the productivity of the land. Evapotranspiration (ET) from land surfaces is one of the key components of the water balance responsible for water loss. Evapotranspiration is of prime interest for various environmental applications, like optimization of irrigation water, irrigation system performance, water deficit for crops, etc. Also, poor irrigation timing and insufficient water application are common factors responsible for limiting agriculture production in many arid and semi‐arid agricultural areas. To address these issues, geospatial technology has emerged as a powerful tool to monitor irrigated lands over various climatic conditions