SWPT: An automated GIS-based tool for prioritization of sub-watersheds based on morphometric and topo-hydrological factors

© 2019 China University of Geosciences (Beijing) and Peking University The sub-watershed prioritization is the ranking of different areas of a river basin according to their need to proper planning and management of soil and water resources. Decision makers should optimally allocate the investments to critical sub-watersheds in an economically effective and technically efficient manner. Hence, this study aimed at developing a user-friendly geographic information system (GIS) tool, Sub-Watershed Prioritization Tool (SWPT), using the Python programming language to decrease any possible uncertainty. It used geospatial–statistical techniques for analyzing morphometric and topo-hydrological factors and automatically identifying critical and priority sub-watersheds. In order to assess the capability and reliability of the SWPT tool, it was successfully applied in a watershed in the Golestan Province, Northern Iran. Historical records of flood and landslide events indicated that the SWPT correctly recognized critical sub-watersheds. It provided a cost-effective approach for prioritization of sub-watersheds. Therefore, the SWPT is practically applicable and replicable to other regions where gauge data is not available for each sub-watershed

Assessment of coastal watershed erosion potential using geographic information systems and expert input for decision support

Sediment is a major impairment in many streams and rivers in the drainage basins along the northern Gulf of Mexico. The use of geospatial technologies improves assessment and decision making for the management of environmental resources and conditions for coastal watersheds. This research focuses on the development of a conceptual qualitative model enhanced with expert input for the assessment of soil erosion potential in coastal watersheds. The conceptual model is built upon five layers (slope, precipitation, soil brightness or exposure, Kactor, and stream density) like those in a standard numerical soil loss model such as the Revised Universal Soil Loss Equation (RUSLE). The conceptual model produced a continuous surface to index erosion potential. Pearson’s correlation coefficient was used to identify variable sensitivity. The model was most sensitive to Kactor variable, followed by soil brightness, stream density, and slope. The model was not sensitive to the precipitation variable due to the lack of variability across the watershed. Expert input was added to the conceptual model for erosion potential with the Analytical Hierarchy Process (AHP). The AHP is used to value the importance of criteria, providing a quantitative weight for the qualitative data. The expert input increased the overall importance of topographic features and this increased cell counts in the upper erosion potential classes. The AHP weights were altered in 1% increments ranging from plus to minus 20% producing 201 unique runs. A quartile analysis of the runs was used to define areas of model agreement. The quartile analysis allowed for the application of an analysis mask to identify areas of increased erosion potential for improved management related decisions. The conceptual and AHP erosion potential output data, including watershed management priority rankings, were published as web mapping services for story map development as a transition to a decision support system. The limits of the story map to allow user interactions with model output rendered an unacceptable platform for decision support. The story map does offer an alternative to static reports and could serve to improve dissemination of spatial data as well as technical reports and plans like a watershed management plan

Identifying Suitable Watersheds across Nigeria Using Biophysical Parameters and Machine Learning Algorithms for Agri–Planning

Identifying suitable watersheds is a prerequisite to operationalizing planning interventions for agricultural development. With the help of geospatial tools, this paper identified suitable watersheds across Nigeria using biophysical parameters to aid agricultural planning. Our study included various critical thematic layers such as precipitation, temperature, slope, land-use/land-cover (LULC), soil texture, soil depth, and length of growing period, prepared and modeled on the Google Earth Engine (GEE) platform. Using expert knowledge, scores were assigned to these thematic layers, and a priority map was prepared based on the combined weighted average score. We also validated priority watersheds. For this, the study area was classified into three priority zones ranging from ‘high’ to ‘low’. Of the 277 watersheds identified, 57 fell in the high priority category, implying that they are highly favorable for interventions. This would be useful for regional-scale water resource planning for agricultural landscape development

Prioritization of water management under climate change and urbanization using multi-criteria decision making methods

This paper quantifies the transformed effectiveness of alternatives for watershed management caused by climate change and urbanization and prioritizes five options using multi-criteria decision making techniques. The climate change scenarios (A1B and A2) were obtained by using a statistical downscaling model (SDSM), and the urbanization scenario by surveying the existing urban planning. The flow and biochemical oxygen demand (BOD) concentration duration curves were derived, and the numbers of days required to satisfy the environmental flow requirement and the target BOD concentration were counted using the Hydrological Simulation Program-Fortran (HSPF) model. In addition, five feasible alternatives were prioritized by using multi-criteria decision making techniques, based on the driving force-pressure-state-impact-response (DPSIR) framework and cost component. Finally, a sensitivity analysis approach for MCDM methods was conducted to reduce the uncertainty of weights. The result indicates that the most sensitive decision criterion is cost, followed by criteria response, driving force, impact, state and pressure in that order. As it is certain that the importance of cost component is over 0.127, construction of a small wastewater treatment plant will be the most preferred alternative in this application

Potential of natural groundwater recharge in the Chennai Basin with a special emphasis on the urban area

Groundwater is the primary source of drinking water in India, and the Chennai River Basin (CRB) is no exception. However, available resources of both groundwater and surface water, are constantly decreasing because of overexploitation and contamination. Well fields in the northern part of the CRB control the water supply for the region, including the Chennai Metropolitan Area (CMA), the capital of the state of Tamil Nadu. Thus, any changes in groundwater storage and availability in the basin directly affect the 11-million people who live in the CMA. So, even though the focus of this study is on the CMA, the entire basin must be considered in order to understand the hydrogeological condition and groundwater situation. This research aims to provide a holistic study of the topographic condition of the basin, the amount of water stress, the identification and mapping of the groundwater potential zones, a review of the groundwater recharge estimation techniques on national scale, and most importantly, the creation of an estimate of the natural groundwater recharge in the CRB and how climate and landuse patterns affect the recharge process. A critical review has been made of popular groundwater recharge estimation practices. The suitability of each method is found to be dependent on time-space, hydrogeological condition, and data availability. Considering the hydrogeological and climatic conditions, the Water Table Fluctuation (WTF) method is the most appropriate method of recharge estimation. Groundwater recharge is largely controlled by topographical factors such as morphometric and hypsometric analysis and understanding these factors is necessary in water resource development planning. Shuttle Radar Topographic Mission (SRTM) and Digital Elevation Model (DEM) data were used in the Geographical Information System (GIS) platform to derive the morphometry and hypsometry. The CRB is an elongated basin of the 7th order and has been classified into 11 sub-basins. Major linear, areal and relief aspects were calculated and discussed based on their hydrologic significance. Steep slopes in the basin may affect the infiltration rate and, subsequently, recharge. Hypsometric curves show the concave type for most of the sub-basins, indicating an old stage. These results provide vital information about the hydrological conditions of the basin. Protecting the resource from depletion and identifying potential zones is essential for sustainable development. Remote Sensing (RS) and GIS technologies with field data were used to map groundwater potential zones in the CRB. For the most accurate results, a total of 11 controlling factors were brought into the GIS platform and a multi-criteria decision making (MCDM) tool, Analytical Hierarchal Process (AHP), was also used. Based on this analysis, groundwater potential zones were classified into five categories- very poor, poor, moderate, good, and very good. The final groundwater potential map showed that 35% of the total area has good to very good groundwater potential, 27% has moderate potential, and 38% has poor to very poor potential. Comparison of the specific capacity obtained from borehole data with these results showed that the predicted groundwater potential identified in this study matches 80% of the area. Groundwater potential depends on climatic conditions such as droughts, atmospheric temperatures, and monsoonal patterns. Using long-term temperature and rainfall data, meteorological drought has been calculated and agricultural drought has been determined using NDVI, NDWI and VCI indices. Agricultural drought indices showed that the vegetation is healthy in the northern and southern regions. However, more than 40% of the area was found to be water stressed. The calculation was made on a decadal scale and the highest water stress was observed in the year 2010. Agricultural drought is more prominent than meteorological drought in the CRB. Chennai faces a severe water shortage in the summer season and flooding in the rainy seasons. The groundwater recharge rate for the Chennai River Basin has been estimated using the empirical method, the rainfall infiltration (RIF) technique, a GIS based distributed model, and the Water Table Fluctuation (WTF) method. The average groundwater recharge rates for different methods vary, with results of 196mm/ year (Empirical formula), 127mm/year (WTF method) and 122mm/year (RIF method). The ratio of effective recharge to rainfall is found as 10% for RIF and WTF methods and 16% using the empirical formula. Considering the conditions in India, as recommended by the Groundwater Estimation Committee (GEC), the WTF method was found to be the most reliable. Still, using multiple methods is suggested for a more fully accurate estimate. This is one of the first extensive studies that covers aspects such as terrain characteristics, proposing the most suitable groundwater recharge estimating methods, groundwater potential zone identification, water stress analysis and natural groundwater recharge estimations in the Chennai River Basin. During this study, large amount of field data on water level, atmospheric temperature, rainfall, and aquifer parameters was collected from different institutions and brought into a single scale. All this data has been brought into the GIS platform and created maps. Thus, a baseline has been created for future groundwater studies. After considering variable recharge estimates and the effective recharge ratio (approx. 10%), it is suggested that groundwater recharge be improved either by repairing existing structures or implementing artificial recharge structures based on the groundwater potential identified. This thesis contains both basic and advanced levels of scientific information, all that is necessary for policymakers to begin improvements, and even provides a number of recommendations for the most effective approach to groundwater management.Das Grundwasser stellt in Indien die wichtigste Quelle zur Gewinnung des Trinkwassers dar. Das Flusseinzugsgebiet Chennai (CRB) bildet dabei keine Ausnahme. Durch Übernutzung und Verunreinigung schwinden jedoch verfügbare Wasserressourcen, sowohl Grundwasser als auch Oberflächenwasser, stetig. Die sich im nördlichen Teil des Flussbeckens befindenden Brunnenfelder kontrollieren die Wasserversorgung der Region, einschließlich der Metropolregion Chennai (CMA) und somit der Hauptstadt des Bundesstaats Tamil Nadu. Aus diesem Grund haben jegliche Änderungen des Grundwasserspeichers und -verfügbarkeit im Flussbecken direkte Auswirkungen auf die 11 Millionen Einwohner der Metropolregion. Obwohl der Fokus dieser Arbeit auf der Metropolregion Chennai liegt, muss zum Verständnis der hydrogeologischen Verhältnisse und der Grundwassersituation das ganze Flussbeckens berücksichtigt werden. In dieser Arbeit wird eine ganzheitliche Betrachtung der topografischen Verhältnisse des Flussbeckens, der Stärke des Wasserstresses, der Bestimmung und Abbildung der möglichen Grundwasserzone, einer Überprüfung der Ermittlungsverfahren zur Grundwasserneubildung auf nationaler Ebene und, am wichtigsten, der Ermittlung der natürlichen Grundwassererneuerung im Flussbecken Chennai sowie der Weise, wie Klima- und Bodennutzungsmuster diesen Erneuerungsprozess beeinflussen, durchgeführt. Die gängigsten Praktiken zur Ermittlung der Grundwassererneuerung wurden kritisch untersucht. Es wurde festgestellt, dass die Eignung der einzelnen Methoden von den Raum- Zeit-Bedingungen, hydrogeologischen Umständen und der Datenverfügbarkeit abhängt. Bei Berücksichtigung der hydrogeologischen und klimatischen Bedingungen stellt die WTF-Methode (Water Table Fluctuation) die passendste Methode zur Ermittlung der Grundwassererneuerung dar. Die Grundwassererneuerung wird größtenteils von den topografischen Faktoren, wie der morphometrischen und hypsometrischen Analyse, bestimmt. Das Verstehen dieser Faktoren ist für die Planung der Wasserressourcenentwicklung unerlässlich. Für die Durchführung der Merphometrie und der Hypsometrie wurden SRTM- und DHM-Daten in geografische Informationssysteme (GIS) eingesetzt. Das Flusseinzugsgebiet Chennai ist ein längliches Becken der 7. Ordnung und wird in 11 Unterbecken unterteilt. Die wichtigsten Linear-, Areal- und Reliefaspekte wurden anhand ihrer hydrologischen Bedeutung berechnet und überprüft. Steilhänge in Becken können die Infiltrationsrate und somit die Grundwassererneuerung beeinflussen. Die hypsografischen Kurven der meisten Unterbecken weisen eine konkave Form vor und geben somit ihre Altersstufe an. Diese Ergebnisse bieten entscheidende Informationen über die hydrologischen Verhältnisse des Beckens. Der Schutz vor der Erschöpfung der Ressource und die Bestimmung der möglichen Zonen ist für eine nachhaltige Entwicklung unumgänglich. Die Felddaten der Fernerkundung und GIS-Technologien wurden zur Abbildung der möglichen Grundwasserzonen im FlusseinzugsgebietChennai eingesetzt. Um ein genaues Ergebnis erzielen zu können, wurden in die GIS-Plattform insgesamt 11 Kontrollfaktoren eingebracht und ein Hilfsmittel für mehrkriterielle Entscheidungen, ein analytischer Hierarchieprozess (AHP), genutzt. Aufgrund dieser Analyse wurden die möglichen Grundwasserzonen in fünf Kategorien eingeteilt: sehr schwach, schwach, mittel, gut und sehr gut. Die endgültige Karte der möglichen Grundwasserzonen zeigt, dass 35 % des Gesamtbereichs über ein gutes bis sehr gutes Grundwasserpotential, 27 % über ein mittleres Potential und 38 % über ein schwaches bis sehr schwaches Grundwasserpotential verfügen. Vergleiche der spezifischen Kapazität, die aus dem Bohrlochdaten gewonnen wurden, mit diesen Ergebnissen zeigen, dass das in dieser Arbeit vorhergesagte Grundwasserpotential zu 80% des Gebiets passt. Das Grundwasserpotential hängt von den Klimabedingungen wie Dürren, Atmosphärentemperaturen und Monsunmustern ab. Durch den Einsatz der Langzeitdaten über Temperatur und Regenfällen wurde die meteorologische Dürre berechnet, die landwirtschaftliche Dürre wurde mittels der Indexe NDVI, NDWI und VCI bestimmt. Die Indexe für die landwirtschaftliche Dürre zeigen, dass sich die Vegetation in den nördlichen und südlichen Gebieten im guten Zustand befindet. Eine Fläche von 40% des Gebiets erlebt jedoch Wasserstress. Die Berechnung erfolgte auf der dekadischen Skala, wobei der höchste Wasserstress im Jahr 2010 zu beobachten war. Im Flusseinzugsgebiet Chennai ist die landwirtschaftliche Dürre starker als die meteorologische Dürre zu spüren. In Chennai herrscht im Sommer gravierender Wassermangel, während der Regenzeit sind jedoch starke Überflutungen vorhanden. Die Grundwasserneubildungsrate für das Flussbecken Chennai wurde anhand der empirischen Methode, des Modells der Regeninfiltration (RIF), eines auf dem GIS-basierten verteilten Modells und der WTF-Methode ermittelt. Die durchschnittliche Grundwasserneubildungsrate variiert je nach Methode/Modell und zeigt die Ergebnisse von 196mm/Jahr (empirische Formel), 127mm/Jahr (WTF-Methode)und122mm/Jahr(RIF-Methode) vor. Der auf den Regen zurückgehender Anteil der effektiven Erneuerung liegt bei den Methoden RIF und WTF bei 10%, bei dem Einsatz der empirischen Formel erreicht dieser Anteil 16%. In Anbetracht der in Indien herrschenden Verhältnisse wurde die WTF-Methode, wie vom indischen Komitee für Grundwasserermittlung (GEC) empfohlen, als die zuverlässigste Methode bestimmt. Für eine möglichst genaue Ermittlung wird jedoch empfohlen, mehrere Methoden zu nutzen. Diese Arbeit gehört zu den ersten ausführlichen Studien, die sich mit Aspekten wie den Geländeeigenschaften, einer Empfehlung der geeignetsten Methoden zur Ermittlung der Grundwasserneubildung, der Bestimmung der möglichen Grundwasserzonen, der Wasserstressanalyse und der Ermittlung der natürlichen Grundwasserneubildung im Flussbecken Chennai beschäftigen. In dieser Arbeit wurde von diversen Einrichtungen eine hohe Zahl an Felddaten über den Wasserstand, Atmosphärentemperatur, Regenfälle und aquiferspezifische Parameter erworben und in einer Skala zusammengeführt. Alle diese gesammelten Daten wurden in die GIS-Plattform eingetragen und es wurden Karten erstellt. Somit wurde eine Ausgangsbasis für zukünftige Grundwasserstudien geschaffen. In Anbetracht der variablen Ermittlungswerte und des effektiven Erneuerungsanteils (etwa 10%) wird empfohlen, die Grundwasserneubildung entweder durch die Sanierung vorhandener Strukturen oder durch den Einsatz künstlicher Anreicherungsstrukturen auf der Grundlage des bestimmten Grundwasserpotentials zu verstärken. Es werden wissenschaftliche Basisinformationen vorgelegt, welche den Entscheidungsträgern zur Optimierung einer angepassten und nachhaltigen Wasserbewirtschaftung dienen können

GIS-based multi-criteria decision making for delineation of potential groundwater recharge zones for sustainable resource management in the Eastern Mediterranean: a case study

In light of population growth and climate change, groundwater is one of the most important water resources globally. Groundwater is crucial for sustaining many vital sectors in Syria, including industrial and agricultural sectors. However, groundwater exploitation has significantly escalated to meet different water needs especially in the post-war period and the earthquake disaster. Therefore, the goal was this study delineation of the groundwater potential zones (GPZs) by integrating the analytic hierarchy process (AHP) method in a geographic information systems (GIS) within the AlAlqerdaha river basin in western Syria. In this study, ten criteria were used to map the spatial distribution of GPZs, including slope, geomorphology, drainage density, land use/land cover (LU/LC), lineament density, lithology, rainfall, soil, curvature and topographic wetness index (TWI). GPZs map was validated by using the location of 74 wells and the Receiver Operating Characteristic Curve (ROC). The findings suggest that the study area is divided into five GPZs: very low, 21.39 km2 (10.87%); low, 52.45 km2 (26.65%); moderate, 65.64 km2 (33.35%); high, 40.45 km2 (20.55%) and very high, 16.90 km2 (8.58%). High and very high zones mainly corresponded to the western regions of the study area. The conducted spatial modeling indicated that the AHP-based GPZs map showed a remarkably acceptable correlation with wells locations (AUC = 87.7%, n = 74), demonstrating the precision of the AHP–GIS as a rating method. The results of this study provide objective and constructive outputs that can help decision-makers to optimally manage groundwater resources in the post-war phase in Syria

Using Geographic Information Systems and Multi-Criteria Decision Analysis to Determine Appropriate Locations for Rainwater Harvesting in Erbil Province, Iraq

Water scarcity is a prominent consequence of global climate change, presenting a significant challenge to the livelihoods of wide parts of the world, particularly in arid and semi-arid regions. This study focuses on Erbil Province in Iraq, where the dual effects of climate change and human activity have significantly depleted water resources in the past two decades. To address this challenge, rainwater harvesting (RWH) is explored as a viable solution. The purpose of this study is to make a suitability zone map that divides the study area into several classes based on the features of each area and its ability to collect rainwater. The map will then be used to find the best place to build different RWH structures. Seven different layers are used to make the RWH suitability zone map: rainfall, runoff, land use/cover (LU/LC), soil texture, slope, drainage density, and the Topographic Wetness Index (TWI). Each layer was assigned specific weights through the Analytical Hierarchy Process (AHP), considering its relevance to RWH. Results revealed four suitability classes: very highly suitable 1583.25 km2 (10.67%), highly suitable 4968.55 km2 (33.49%), moderately suitable 5295.65 km2 (35.69%), and lowly suitable 2989.66 km2 (20.15%). Notably, the suitability map highlights the northern and central regions as particularly suitable for RWH. Furthermore, the study suggested three suitable locations for constructing medium dams, six for check dams, and twenty-seven for farm ponds, according to the requirements of each type. These findings provide valuable insights for the strategic planning and effective management of water resources in the study area, offering potential solutions to the pressing challenges of water scarcit

AHPとシステムダイナミクスを用いた持続可能な水資源管理のための河川再生政策の評価

The focus of this study is to assess river restoration efficiently according to the users of the rivers. The AHP method is used to select the priority of river restoration goals were: restoration of species, restoration of ecosystems or landscapes and restoration of ecosystem services. The next step is to assess water balance in a river basin using a hydrological model to calculate water availability and use a water demand model to calculate water requirements. The hydrological model used was chosen between the NRECA and FJ. Mock. The last step is to build a system dynamics model consisting of population sub-models, water storage, and water demand. The SD model is to assess the impact of river restoration plans were: reclaimed water, increased water demand efficiency, reduction of agricultural land, and inter-basin water transfer. The case study used is the Ciliwung River Basin which has a　high population and economic growth.北九州市立大

Distribution of Flood Risk Area in Bodri Watershed of Kendal Regency

Flooding is a catastrophic phenomenon that can occur due to various factors, such as uncontrolled land-use changes, climate change, and weather anomalies, and drainage infrastructure damage. The Bodri watershed in Kendal Regency is one of the watersheds in Central Java, which is categorized as critical based on Decree No. 328/Menhut-II/2009. Some of the problems in the Bodri watershed include land use that is not suitable for its designation, flooding, erosion, and landslides. This study aims to conduct spatial modeling to create flood hazard maps and flood risk level maps in the Bodri watershed. The method used is hydrograph analysis, flood modeling, analysis of potential flood hazards, and analysis of flood risk levels. Analysis of the potential for flood hazards from the spatial modeling inundation map with the input of the flood peak return period of 2 years (Q2), 5 years (Q5), and 50 years (Q50). Vulnerability analysis based on land use maps of flood hazard areas. The distribution of flood-prone areas in the Bodri watershed is in Pidodo Kulon Village, Pidodo Wetan Village, and Bangunsari Village

Determinación del índice de calidad del suelo en el delta de Batumi, Georgia

The soil quality index is a quantitative assessment concept and it is used in the evaluation of ecosystem components. Because of the high potential for agriculture and biodiversity, deltas are the most valuable parts of the ecosystem. This study aimed to determine the soil quality index (SQI) in the Batumi Delta, Georgia. For this purpose, the study area was divided into five plots due to their morphological positions (L1, L2, L3, L4, and L5). A total of 125 soil samples were taken for analysis including clay content (CC), silt content (SC), sand content (SaC), mean weight diameter (MWD), aggregate stability (AS), amount of water retained under -33 kPa (FC) and -1500 kPa (WP) pressures and organic matter content (OM). These properties were used as the main criteria, and the Analytic Hierarchy Process (AHP) and Factor Analysis were used for weighting them. Sub-criteria were scored using expert opinion and the linear score functions, such as “more is better” and “optimum value”. For determining SQI, the additive method (SQIA), the weighted method with AHP (SQIAHP), and the weighted method with factor analysis (SQIFA) were used. The resulting SQI scores of the three methods were ordered as SQIAHP>SQIA>SQIFA, but these differences were not significant. However, the SQI scores of the plots (p£0.01) showed statistically significant differences and were ordered as L5>L4>L3>L2>L1.El índice de calidad del suelo es un concepto de evaluación cuantitativa y se utiliza en la evaluación de los componentes del ecosistema. Debido a su potencial alto para la agricultura y la biodiversidad, los deltas son las partes más valiosas del ecosistema. Este estudio tuvo como objetivo determinar el índice de calidad del suelo (SQI) en el delta de Batumi, Georgia. Es por ello que el área de estudio se dividió en cinco parcelas con base en sus posiciones morfológicas (L1 , L2 , L3 , L4 y L5 ). Un total de 125 muestras de suelo se tomaron para su análisis, e incluyeron contenido de arcilla (CC), contenido de limo (SC), contenido de arena (SaC), diámetro medio ponderado (MWD), estabilidad de agregados (AS), cantidad de agua retenida de presiones por debajo de -33 kPa (FC) y -1500 kPa (WP) y contenido de materia orgánica (OM). Estas propiedades se utilizaron como criterios principales, y para ponderarlas usamos el Proceso analítico jerárquico (Analytic Hierarchy Process, AHP) y el Análisis de factores. Los subcriterios se calificaron de acuerdo con la opinión de expertos y con las funciones de calificación lineal, como “más es mejor” y “valor óptimo”. Para determinar el SQI, se utilizó el método aditivo (SQIA), el método ponderado con AHP (SQIAHP) y el método ponderado con análisis de factores (SQIFA). Los valores resultantes de SQI de los tres métodos se ordenaron como SQIAHP> SQIA> SQIFA, pero estas diferencias no fueron significativas. Sin embargo, los valores de SQI de las parcelas (p£0.01) mostraron diferencias estadísticamente significativas y se ordenaron como L5 > L4 > L3 > L2 > L