Hydrological Ecosystem Services Research Articles

Nature's Contributions to People: Systematic Mapping of Studies and Inventory of Methodologies and Indicators for Quantifying Hydrological Ecosystem Services

Objective: Evaluate the estimation of nature's contributions to people - NCP (i.e. ecosystem services - ES) through bibliographic mapping and systematization of methodologies, tools and indicators of hydrological ecosystem services (HES). Theoretical Framework: Predatory exploitation of ecosystems is causing increasingly severe impacts on humanity. Accelerated by population growth, changes in land use and the decoupling of measures recommended by science from those adopted by nations, climate change is triggering alterations in the global hydrological cycle. Adaptation strategies depend on the production of information on the supply and flow of HES. Method: Consultation of the Web of Science, Scopus and Science Direct databases, and systematic bibliographic mapping (2014-2024), with bibliometric analysis in the VOSviewer software, and recording of information on NCP, ES, metrics, methodologies for quantifying HES and respective indicators. Results and Discussion: A total of 743 abstracts were analyzed and 196 articles were selected. Of these, 103 estimated HES, with a predominance of studies on a river basin scale. Seventy-nine indicators were mapped, mostly biophysical, associated with water flow regulation and water quality. China was the most represented country in terms of mapped area. The most widely used models were InVEST and SWAT. Research Implications: Systematization of information for users interested in mapping and quantifying HES, with an indication of established aspects, methods, and knowledge gaps. Originality/Value: Mapping based on HES indicators, aggregation of studies under different ES frameworks and provision of a dynamic results panel, with spatialization of studies and various data filtering possibilities.

Economic Assessment of Hydrologic Ecosystem Services in Morocco’s Protected Areas: A Case Study of Ifrane National Park

This study delves into the complex interplay between land use dynamics, hydrological services, and intangible benefits within the context of Ifrane National Park (INP) in Morocco. Due to its extensive mountain forests and numerous wetlands, INP is a crucial contributor to the nation’s water supply and a vital source of hydrological ecosystem services (HES). However, climate change and evolving land use patterns have led to diminishing water resources and the desiccation of certain wetlands. This research used the Integrated Valuation of Ecosystem Services and Tradeoffs software (InVEST 3.10.2) for HES quantification and environmental economics approach for monetization to comprehend how HES values respond to challenges posed by urbanization, intensive agriculture, and other land use alterations. This work underscores INP’s role as a significant “water tower”, emphasizing the evolution of its services amidst challenges. Our findings reveal an annual decrease in HES economic value by USD 4000. This economic assessment serves as a compelling tool to enlighten decision-makers and park users about the imperative need to preserve natural ecosystems and use water resources judiciously. It advocates for investments in conservation and restoration within protected areas to sustain these vital services.

Identifying Conservation Priority Areas of Hydrological Ecosystem Service Using Hot and Cold Spot Analysis at Watershed Scale

Identifying Conservation Priority Areas of Hydrological Ecosystem Service Using Hot and Cold Spot Analysis at Watershed Scale

Analysis of the watershed social-ecological system trajectory in Copalita-Huatulco, Mexico: The impact of drivers on hydrological ecosystem services.

In watersheds, which function as social-ecological systems (SESs), hydrological ecosystem services (HESs) are crucial flows connecting natural and social components. The internal and external drivers that shape HESs and watershed SES trajectories create complexities in watershed management. In this study, the adaptive cycle framework was adopted, and a qualitative method is proposed to analyze the impacts of drivers on the HES and the watershed SES trajectory. Empirical evidence from the Copalita-Huatulco watershed in Mexico was used to study the relationships between drivers and HESs. The results reveal changes in regional hydrodynamics due to natural shocks, cumulative social stressors, and SES-related human trajectories. The SES trajectory was in a growth phase when stressors dominated, a collapse when shocks occurred, and a conservation phase when human agency was strong. Understanding the impact of drivers on HESs and their integration into SES trajectories is a key element of HES resilience.

Enhanced Hydrologic Connectivity and Solute Dynamics Following Wildfire and Drought in a Contaminated Temperate Peatland Catchment

AbstractIntact peatlands provide hydrological ecosystem services, such as regulating water regimes and immobilizing pollutants within catchments. Climate change impacts including drought and wildfire may impair their functioning, potentially impacting ecosystem service delivery. Here we investigate stream water quality changes following the combined impacts of a summer drought and wildfire in a peat‐dominated catchment in the UK during 2018. The study catchment stores legacy pollutants (i.e., metals) due to past industrial activity, thus making it particularly susceptible to pollutant release during wildfires. We quantified changes in water chemistry during five storm events over a 9‐month period following the wildfire. Concentration‐discharge (C‐Q) relationships for nine solutes were analyzed to explore changes in activation and connectivity of solute source zones. Hysteresis and flushing indices of C‐Q responses further described solute dynamics during storm events. We found that most nutrient and base cation concentrations in the stream discharge were highest in the immediate post‐fire storm events and decreased during subsequent autumn and spring storms. Metal concentrations increased during autumn and spring storms, indicating delayed mobilization from within‐peat or distal headwater sources. Our findings suggest that seasonal re‐wetting and hydrologic connectivity following disturbance influenced solute source zone activation and transport in the study catchment. Water quality responses associated with wildfire and drought were primarily observed in the months following the wildfire, suggesting mobilization of pollutants peaks shortly after fire. Our results contribute to a critical understanding of the future of water quality risks in temperate peatland catchments subject to disturbances exacerbated by climate change.

Current hydrological ecosystem services and potential impacts of business-as-usual land abandonment at the national scale for Spain

This research demonstrates the opportunities and challenges for decision-makers in the use of satellite data driven hydrological model such as WaterWorld to assess current hydrological ecosystem services at the national scale and evaluate the impact of land use scenarios for the future. Spain has been selected as a case study in view of the negative consequences for hydrological ecosystem services caused by land abandonment over the last few decades, which, if action is not taken soon, will make Spain the European Union country most affected by this problem in the coming years. The results show that continued land abandonment will exacerbate the already geographically polarised situation of land abandonment of agricultural areas in the north of the country due to their low economic viability, in contrast to intensification of irrigated area in the most arid regions of Spain, leading to an increase in water balances in the already wet areas and a decrease in the arid areas. However, there is much to be gained from restoration of nature in Spain. Beyond the obvious benefits for biodiversity, climate change mitigation and recreation, abandonment of current agricultural land and its return to natural cover will lead to improvements in water quality ecosystem services. This model used, which is easily replicable to other countries given the availability of a user-friendly interface and embedded global data, can help analyse hydrological ecosystem services in any other country in the world. Like all models and measurements, WaterWorld has limitations so results should be viewed critically, but can still contribute to discussions on land management for sustainability, alongside other source of information.

ANALYSIS OF METHODS OF SATELLITE MONITORING OF CHANGES IN WATER BODIES

Surface waters are part of the ecosystem services of various countries of the world, mainly intended for domestic, industrial and agricultural use, production of food, electricity (hydropower), obtaining medicinal substances and other materials from biota, organization of places of rest and recreation. Seasonal monitoring of the level of surface water allows obtaining a qualitative characteristic and quantitative assessment of changes in the hydrological ecosystem service as a result of climate changes and anthropogenic influences. In this regard, technologies for operational monitoring of the dynamics of changes in water bodies play an important role.

Vulnerability assessment of hydrological ecosystem services under future climate and land use change dynamics

Hydrological Ecosystem Services (HESs), as an important part of ecosystem services, are those services that depend on hydrological processes. HESs vulnerability assessment at the watershed scale is used to explore highly vulnerable areas for management and protection measures. This study aimed at developing a method for HESs vulnerability assessment and achieve a quantitative integrated index under future climate and land use change scenarios. We focused on three regulating HESs, including water flow regulation, erosion regulation, and local climate regulation (LC). An integrated model of Markov chain and automatic cells was used to predict land use changes. Future climate data were estimated using the Climate Change Toolkit (CCT). The Soil and Water Assessment Tool (SWAT) model was developed for HESs vulnerability assessment in the Taleghan Watershed in Iran. The model was calibrated by river discharge using the Sequential Uncertainty Fitting (SUFI-2) and the Parallel Processing option. The results show that sub-watersheds with higher precipitation (PCP) and lower evapotranspiration (ET) are more efficient in water flow and local climate regulation. However, sub-watersheds with lower PCP and higher ET are more vulnerable to erosion. Changes in water flow regulation services and local climate regulation were more consistent with climate changes, and conversely, changes in erosion and sediment regulation services had a very high level of compliance with land use changes. The method applied in this study can easily be adapted to other regions to identify areas with more vulnerability and less resilience in improving the water and soil structure and function in the watershed.

Estimation of Water Yield and Soil Erosion in Samanalawewa Watershed in Sri Lanka using GIS-based InVEST Model

Ecosystem services (ES) are a group of tasks performed by the earth's ecosystems that are required to support life and offer benefits to humanity. Thus, this study explores two of the water-related ecosystem services, water yield, and soil retention that were distributed in the Samanalawewa Watershed (SW) and its eight sub-watersheds in Sri Lanka, over 20 years (2000-2020) with five- year time intervals. Soil and water conservation and water yield play an important role in ecosystem management. Hydrological balance is a crucial component of the hydrological ecosystem services. Assessing water yield and soil erosion are pivotal for watershed management. Thus, this study estimated and mapped the water yield and soil erosion, using the Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST 3.9.2) Annual Water Yield (AWY) and Sediment Delivery Ratio (SDR) model respectively. According to the obtained results, in 2000, 2005, 2010, 2015 and 2020, the estimated mean annual water yield was 2.62x105, 2.6x105, 3.5x105, 3.58x105 and 2.75x105 m3 ha-1year-1, respectively. Furthermore, the estimated mean annual soil erosion rates for the above- mentioned years were 53.2, 52.9, 69.7, 87.7 and 70.2 t ha-1 year-1. The estimated soil loss values of the SW are 10 to 18 times greater than the soil erosion tolerance (5 t ha-1 year-1) in Sri Lanka. The results show that the years 2015 and 2005 have the highest and the lowest water yield and total soil loss values, respectively. The upper part of the watershed has relatively moderate water yield and soil loss values than the lower part. These findings would be beneficial in developing watershed management strategies and in the implementation of suitable soil and water conservation techniques within the watershed. 
 Keywords: Ecosystem services, InVEST, Samanalawewa watershed, Soil erosion, Water yield

Response of hydrological ecosystem services to land-use change and risk assessment in Jiangxi Province, China

Water bodies provide humans with important hydrological ecosystem services (HESs), directly or indirectly. Water yield, water conservation, and soil conservation are essential to HESs. Since China's reform and opening up, and with its rapid socio-economic development, land use in Jiangxi Province has undergone drastic change, resulting in threats to the ecological environment. This paper evaluates three HESs, water yield, water conservation, and soil conservation, in Jiangxi Province based on land use and rainfall data, quantifies the impacts of different land classes on each ecosystem, predicts future land use using the patch-generating land use simulation (PLUS) model, and finally, discusses the ecological risks in the study area. The following results were obtained: (1) The HESs in the basin increased and then decreased from 2000 to 2020, and the spatial distribution of water yield and water conservation was greatly influenced by rainfall. Soil conservation was mostly consistent with the elevation distribution. (2) Over time, the overall aggregation of HESs in the study area increased. There were small differences in the effects of various land uses on water yield and water conservation, and large differences in the effects on soil conservation. (3) The distribution of ecological risks was not affected by different land use strategies, with the lower ecological risk level 1 dominating. Most risk areas were present in Ganzhou, Ji'an, Shangrao, and Jiujiang. The ecological risk from urban sprawl (US) accounted for the most significant proportion, and that from the ecological protection (EP) strategy accounted for the lowest proportion. This study provides reference for sustainable land use development and ecological risk prevention in the study area.

HYDROLOGICAL MODELING USING SWAT IN THE DECISION-MAKING PROCESS FOR THE CONSERVATION OF RIVER BASINS.

The conservation of watersheds is a concern in all countries because of the scarcity of water for capitation and use and the anthropogenic degradation of this natural resource. Thus the objective of this study is to make a systematic review on the themes ecosystem service, hydrological modeling using the SWAT model. Emphasizing the importance of this theme in the decision-making process in the management of water resources. The research is exploratory, having as main method the literature/scientific review. The bibliographic survey used was carried out on the Scopus platform, in chronological order in the range from 2018 to 2022. The two years of the health crisis were the years of greatest scientific production. Two publications stood out for the number of citations: A review of SWAT Applications, performance and Future needs for Simulation of Hydro-Climatic Extremes and, Comparison of the SWAT and Invest models to determine hydrological Ecosystem service Spatial Patterns, Priorities and trade-offs in a Complex Basin, both published in 2020. The most prominent countries in research publications in the area of Environmental Science were China, USA, Canada, Germany, Brazil and Norway. The relevance of studies involving this theme become evident because they are tools used in the decision-making process in water management, showing up as a vast field for research in Latin America and South America, but specifically in Brazil for its continental dimension and its diversity.

Geospatial modeling of hydrological ecosystem services in an ungauged upper Yamuna catchment using SWAT

Hydrological ecosystem services (HES) are vital for resource allocation, conservation prioritization, and climate change adaptation. However, research gaps persist due to limited understanding of complex hydrological systems and inadequate ground-station data, especially in ungauged watersheds with complex terrains. The present study addresses these gaps by estimating and mapping HES descriptors using regionalization techniques in an ungauged Aglar watershed. Additionally, it conducts a temporal analysis of hydrological fluxes using Soil and Water Assessment Tool (SWAT). Aglar is a constituent sub-watershed of a gauged watershed named Bausan having two discharge observation stations located at Naugaon and Bausan sites in Uttarakhand, India. A nested parameterization approach was adopted to represent the hydrological variabilities over the Bausan watershed with one outlet at Aglar. The stream flow derived from the calibrated Bausan watershed was used as synthetic observations in SWAT model setup for Aglar and found to yield very good statistical results. Calibration yielded coefficient of determination (R2) = 0.91, Nash Sutcliff Efficiency (NSE) = 0.91, and standardized root mean square error (RSR) = 0.29, while the validation yielded R2 = 0.68, NSE = 0.50, and RSR = 0.37. Parameters related to base flow or stream flow were the most sensitive in the model's output. Water balance analysis reveals 36% of precipitation transformed into stream flow, with direct runoff accounting for 72% and base flow for 28%. Forest cover contributed approximately 50.68% of precipitation through evapotranspiration. The study identifies a maximum sediment load of approximately 26 t/ha, indicating fragility of the landscape. Non-parametric tests such as Mann Kendall and Sen's slope indicated increasing trends in surface runoff, lateral flow, water yield, and groundwater recharge. The analysis of the empirical cumulative distribution function demonstrated that all hydrological components exhibit trends similar to precipitation. Spatially and temporally, variations in HES provisioning were observed, with forests surpassing non-forest areas. These findings emphasize the value of HES descriptors in analyzing spatiotemporal changes in HES provisioning and offer valuable insights for policymakers for future policy dialogues. This study lays the groundwork for further investigations into the hydrological processes of ungauged watersheds.

Mapping high-altitude peatlands to inform a landscape conservation strategy in the Andes of northern Peru

SummaryThe wetlands of the jalca ecoregion in the Andes of northern Peru form peat and play a major role in the hydrological ecosystem services of the ecoregion. Although peat is globally valued for carbon sequestration and storage, peatlands have not yet been mapped in the jalca. In this region, the Gocta waterfall, one of the 20 highest waterfalls in the world, depends on the jalca’s wetlands ecosystem. The local population depends on tourism to the waterfall and is concerned about preserving its drainage area. To inform conservation planning, in this study we delimited the drainage area of the Gocta waterfall and identified land tenure by applying Geographic Information System (GIS), remote sensing and participatory mapping techniques. Then, by classifying optical, radar and digital elevation models data, we mapped peatland in the jalca of the Gocta drainage area with an overall accuracy of 97.1%. Our results will inform conservation strategy in this complex area of communal, private and informal land tenure systems. At a regional level, this appears to be the first attempt at mapping peatlands using remote sensing imagery in the jalca ecoregion, and it represents a milestone for future efforts to map and conserve peatlands in other tropical mountain areas of the world.

Economic valuation of the ecosystem services of the water resource of the Cachi river basin, Ayacucho, Perú

Knowing economic value of ecosystem services makes it possible to identify the importance of ecosystems and their services, with which better decisions that have an impact on social well-being are expected. The objective of the study was to estimate the economic value of water ecosystem services (ES), from the Cachi basin.The novelty of the study lies in the application of a complete study of the Contingent Valuation Method (CVM), the Willingness to Pay (WTP) and the Willingness to Accept (WTA) were estimated. According to surveys carried out, 90.6% of the producers in the Cachi basin are WTP, 9.4% are not WTP for economic reasons. On the other hand, 92% of the inhabitants of the high Andean areas are WTA, only 8% do not accept an economic incentive, due to disagreements with the Regional Government of Ayacucho. The econometric results of the logit model showed that the producers are WTP, at most S/ 74.87/ha/campaign (19.50 USD), for the conservation of the hydrological ES for agricultural porpuses. While the inhabitants of the highland areas of the Cachi basin are WTA, the minimum amount of S/162.05 ha/bofedal/monthly (42.21 USD), in exchange for conserving the wetlands and pastures of the Cachi basin headwaters. It is concluded, the producers are WTP for obtaining continuity and quality of the supply of water for agricultural use, and they are WTA for the conservation and recovery of natural water sources. Putting these results into practice would contribute to the sustainability of the water supply in the high Andean areas, guaranteeing the provision of water resources to current and future generations in times of drought.

Urban Trees and Hydrological Ecosystem Service: A Novel Approach to Analyzing the Relationship Between Landscape Structure and Runoff Reduction.

Urban stormwater runoff has posed significant challenges in the face of urbanization and climate change, emphasizing the importance of trees in providing runoff reduction ecosystem services (RRES). However, the sustainability of RRES can be disturbed by urban landscape modification. Understanding the impact of landscape structure on RRES is crucial to manage urban landscapes effectively to sustain supply of RRES. So, this study developed a new approach that analyzes the relationship between the landscape structural pattern and the RRES in Tabriz, Iran. The provision of RRES was estimated using the i-Tree Eco model. Landscape structure-related metrics of land use and cover (LULC) were derived using FRAGSTATS to quantify the landscape structure. Stepwise regression analysis was used to assess the relationship between landscape structure metrics and the provision of RRES. The results indicated that throughout the city, the trees prevented 196854.15 m3 of runoff annually. Regression models (p ≤ 0.05) suggested that the provision of RRES could be predicted using the measures of the related circumscribing circle metric (0.889 ≤ r2 ≤ 0.954) and the shape index (r2 = 0.983) of LULC patches. The findings also revealed that the regularity or regularity of the given LULC patches' shape could impact the patches' functions, which, in turn, affects the provision of RRES. The landscape metrics can serve as proxies to predict the capacity of trees for potential RRES using the obtained regression models. This helps to allocate suitable LULC through optimizing landscape metrics and management guidance to sustain RRES.

A New Tool for Mapping Water Yield in Cold Alpine Regions

Watershed management requires reliable information about hydrologic ecosystem services (HESs) to support decision-making. In cold alpine regions, the hydrology regime is largely affected by frozen ground and snow cover. However, existing special models of ecosystem services usually ignore cryosphere elements (such as frozen ground and snow cover) when mapping water yield, which limits their application and promotion in cold alpine regions. By considering the effects of frozen ground and snow cover on water yield, a new version of the Seasonal Water Yield model (SWY) in the Integrated Valuation of Ecosystem Services and Trade-offs (InVEST) was presented and applied in the Three-River Headwaters Region (TRHR) in southeastern Qinghai-Tibetan Plateau (QTP). Our study found that incorporating the effects of frozen ground and snow cover improved model performance. Frozen ground acts as a low permeable layer, reducing water infiltration, while snow cover affects water yield through processes of melting and sublimation. Both of these factors can significantly impact the distribution of spatial and temporal quickflow and baseflow. The annual average baseflow and water yield of the TRHR would be overestimated by 13 mm (47.58 × 108 m3/yr) and 14 mm (51.24 × 108 m3/yr), respectively, if the effect of snow cover on them is not considered. Furthermore, if the effect of frozen ground on water yield were not accounted for, there would be an average of 6 mm of quickflow misestimated as baseflow each year. Our study emphasizes that the effects of frozen ground and snow cover on water yield cannot be ignored, particularly over extended temporal horizons and in the context of climate change. It is crucial to consider their impacts on water resources in cold alpine regions when making water-related decisions. Our study widens the application of the SWY and contributes to water-related decision-making in cold alpine regions.

Accounting for the water related ecosystem services of forests in the Southern Aegean region of Turkey

This study aims to model hydrological ecosystem services provided by forests and explore how they can be captured in an ecosystem accounting framework. We test a dynamic GIS-based hydrological model to quantify and map key hydrological ecosystem services in the Southern Aegean Region of Turkey and integrate the services into an ecosystem account following the System of Environmental Economic Accounting – Ecosystem Accounting (SEEA EA). We map and account for services in physical and monetary terms, using an innovative model to quantify flood control services. Our paper connects forest management with water resource supply, eliciting the hydrological role of forests. The combined value of the three ecological services (groundwater recharge, flood control and sediment control) is about 201 million €/year. Reduction in forest coverage means that the economy will face the consequences of losses of these critical regulating services. Finally, we discuss opportunities, challenges, and limitations in the practical application of the ecosystem accounting concept.

Relative and Cumulative Effects of Climate and Land Use Change on Hydrological Ecosystem Services in Northeast China

Climate change (CC) and land use change (LUC) have been determined as two major environmental change variables that broadly affect hydrological ecosystem services (HESs). However, the relative and cumulative effects of CC and LUC on HES at large spatial scales where there is great environmental heterogeneity is still unclear enough to support the formulation and update of land use decision-making and ecological management policies. This study has quantified the spatiotemporal change of HESs (water yield, water purification, soil retention) from 1992 to 2020 in northeast China, and evaluated the relative contribution and cumulative effects of CC and LUC on HESs through environmental setting scenarios and using two indicators (the Relative Importance Index and the Combined Effects Index). This study yielded the following results: (1) From 1992 to 2020, water yield (WY) (+94.33 mm) and soil retention (SR) (5.28 × 103 t/km2) both showed an upward trend from 1992 to 2020 and an upward trend in nitrogen export (NE) indicating a decline in water purification (WP). (2) There was significant spatial heterogeneity of HESs in northeast China, which included significant increases in WY in the Sanjiang Plain; NE in the Songnen Plain (SNP), Sanjiang Plain (SJP), and Liao River Plain (LJP); and SR in the Greater Khingan Mountains (GKMR), Lesser Khingan Mountains (LKMR), and Changbai Mountains (CBMR). (3) WY was more affected by CC than LUC, especially in the SJP, the eastern LRP, and the southern CBMR; NE was more affected by LUC than CC in the western LRP, the southern GKMR, and the southwestern SNP; SR was more affected by LUC than CC in the GKMR; SR was more affected by CC than LUC and intensity gradually increased in the CBMR and LKMR. (4) The cumulative effect of CC and LUC contributed to HESs in most regions but inhibited HESs in some regions; warming and forestland expansion especially significantly inhibited WY. Our study emphasizes that current land use policies and ecosystem management practices should consider the relative and cumulative effects of CC and LUC on HESs to maintain diverse ecosystem services and ensure human well-being.

Determination of Spatially-Distributed Hydrological Ecosystem Services (HESS) in the Red River Delta Using a Calibrated SWAT Model

The principles of Integrated Water Resources Management (IWRM), conservation of natural capital, and water accounting requires Hydrological Eco-System Services (HESS) to be determined. This paper presents a modeling approach for quantifying the HESS framework using the Soil Water Assessment Tool (SWAT). SWAT was used–after calibration against remote sensing data–to quantify and spatially identify total runoff, natural livestock feed production, fuelwood from natural forests, dry season flow, groundwater recharge, root zone storage for carrying over water from wet to dry season, sustaining rainfall, peak flow attenuation, carbon sequestration, microclimate cooling, and meeting environmental flow requirements. The environmental value of the current land use and vegetation was made explicit by carrying out parallel simulations for bare soil and vegetation conditions and reporting the incremental ecosystem services. Geographical areas with more and fewer HESS are identified. The spatial and temporal variability of annual HESS services is demonstrated for the Day Basin—which is part of the Red River delta (Vietnam)—for the period 2003 to 2013. The result shows that even though the basin is abundant with HESS, e.g., 7482 m3/ha of runoff, 3820 m3/ha of groundwater recharge, the trend for many HESS values, e.g., micro-climate cooling, meeting environmental flow requirements, and rootzone storage, are declining. It is found and proven that quantified HESS indicators highlighted the provisioning and regulating characters of ecosystem services, as well as geographical hotspots across the basin. The SWAT model shows the capability of simulating terrestrial eco-hydrological processes such as climate, soil, and current land use. The methodology illustrates how eco-hydrologists can benchmark ecosystem values and include HESS in exploring river basin management scenarios, climate change studies, and land use planning.

A New Framework of 17 Hydrological Ecosystem Services (HESS17) for Supporting River Basin Planning and Environmental Monitoring

Hydrological ecosystem services (HESS) describe the benefits of water for multiple purposes with an emphasis on environmental values. The value of HESS is often not realized because primary benefits (e.g., food production, water withdrawals) get the most attention. Secondary benefits such as water storage, purification or midday temperature cooling are often overlooked. This results in an incorrect evaluation of beneficial water usage in urban and rural resettlements and misunderstandings when land use changes are introduced. The objective of this paper is to propose a standard list of 17 HESS indicators that are in line with the policy and philosophy of the Consultative Group of International Agricultural Research (CGIAR) and that are measurable with earth observation technologies in conjunction with GIS and hydrological models. The HESS17 framework considered indicators that can be directly related to water flows, water fluxes and water stocks; they have a natural characteristic with minimal anthropogenic influence and must be quantifiable by means of earth observation models in combination with GIS and hydrological models. The introduction of a HESS framework is less meaningful without proper quantification procedures in place. Because of the widely diverging management options, the role of water should be categorized as (i) consumptive use (i.e., evapotranspiration and dry matter production) and (ii) non-consumptive use (stream flow, recharge, water storage). Governments and responsible agencies for integrated water management should recognize the need to include HESS17 in water allocation policies, water foot-printing, water accounting, transboundary water management, food security purposes and spatial land-use planning processes. The proposed HESS17 framework and associated methods can be used to evaluate land, soil and water conservation programs. This paper presents a framework that is non-exhaustive but can be realistically computed and applicable across spatial scales.