Your search found 52 records
1 Walker, D.; Haile, Alemseged Tamiru; Gowing, J.; Legesse, Y.; Gebrehawariat, G.; Hundie, H; Berhanu, D.; Parkin, G. 2019. Guideline: community-based hydroclimate monitoring. Planning, establishing and operating. Oxford, UK: University of Oxford. REACH Programme. 59p. (REACH Working Paper 5)
(Location: IWMI HQ Call no: e-copy only Record No: H049391)
(5.58 MB) (5.58 MB)
2 Young, W. J.; Anwar, Arif; Bhatti, Tousif; Borgomeo, Edoardo; Davies, S.; Garthwaite, W. R. III; Gilmont, M.; Leb, C.; Lytton, L.; Makin, Ian; Saeed, B. 2019. Pakistan: getting more from water. Washington, DC, USA: World Bank. 191p. (Water Security Diagnostics)
(Location: IWMI HQ Call no: e-copy only Record No: H049423)
(9.43 MB) (9.43 MB)
This report builds on prior work to provide a new, comprehensive, and balanced view of water security in Pakistan, stressing the importance of the diverse social, environmental, and economic outcomes from water. The report highlights the complex water issues that Pakistan must tackle to improve water security and sheds new light on conventional assumptions around water. It seeks to elevate water security as an issue critical for national development. The report assesses current water security and identifies important water-related challenges that may hinder progress in economic and human development. It identifies unmitigated water-related risks, as well as opportunities where water can contribute to economic growth and poverty reduction. The report analyzes how the performance and architecture of the water sector are related to broader economic, social, and environmental outcomes. It models alternative economic trajectories to identify where intervention can lead to a more water-secure future. A consideration of water sector architecture and performance and how these determine outcome leads to recommendations for improving aspects of sector performance and adjusting sector architecture for better outcomes. The sector performance analysis considers (a) management of the water resource, (b) delivery of water services, and (c) mitigation of water-related risks. The description of sector architecture considers water governance, infrastructure, and financing.
(Location: IWMI HQ Call no: e-copy only Record No: H049425)
(4.69 MB)
Water diversion projects across the world, for drinking water, energy production and irrigation, have threatened riverine ecosystems and organisms inhabiting those systems. However, the impacts of such projects on aquatic biodiversity in monsoon-dominated river ecosystems are little known, particularly in Nepal. This study examines the effects of flow reduction due to water diversion projects on the macroinvertebrate communities in the rivers of the Karnali and Mahakali basins in the Western Himalayas in Nepal. Macroinvertebrates were sampled during post-monsoon (November), baseflow (February) and pre-monsoon (May) seasons during 2016 and 2017. Nonmetric Multidimensional Scaling (NMDS) was performed to visualize clustering of sites according to percentage of water abstractions (extraction of water for various uses) and Redundancy Analysis (RDA) was used to explore environmental variables that explained variation in macroinvertebrate community composition. A significant pattern of macroinvertebrates across the water abstraction categories was only revealed for the baseflow season. NMDS clustered sites into three clumps: “none to slight water abstraction (< 30% – Class 1)”, “moderate water abstraction (> 30% to < 80% – Class 2)” and “heavy water abstraction (> 80% – Class 3)”. The study also showed that water abstraction varied seasonally in the region (Wilk’s Lambda = 0.697, F(2, 28) = 4.215, P = 0.025, n2 = 0.23). The RDA plot indicated that taxa such as Acentrella sp., Paragenetina sp., Hydropsyche sp., Glossosomatinae, Elmidae, Orthocladiinae and Dimesiinae were rheophilic i.e. positively correlated with water velocity. Taxa like Torleya sp., Caenis sp., Cinygmina sp., Choroterpes sp., Limonidae and Ceratopogoniidae were found in sites with high proportion of pool sections and relative high temperature induced by flow reduction among the sites. Indicator taxonomic groups for Class 1, 2 and 3 water abstraction levels, measured through high relative abundance values, were Trichoptera, Coleoptera, Odonata and Lepidoptera, respectively. Macroinvertebrate abundance was found to be the more sensitive metric than taxonomic richness in the abstracted sites. It is important to understand the relationship between flow alterations induced by water abstractions and changes in macroinvertebrates composition in order to determine sustainable and sound management strategies for river ecosystems.
(Location: IWMI HQ Call no: e-copy only Record No: H049493)
(5.22 MB) (5.22 MB)
(Location: IWMI HQ Call no: e-copy only Record No: H049542)
(18.40 MB)
This study provides statistical emulators of global by gridded crop models included in the Inter-Sectoral Impact Model Intercomparison Project Fast Track project to estimate irrigated crop yields and associated irrigation water withdrawals simulated at the grid cell level. An ensemble of crop model simulations is used to build a panel of monthly summer weather variables and corresponding annual yields and irrigation water withdrawals from five gridded crop models. This dataset is then used to estimate crop-specific response functions for each crop model. The average normalized root mean square errors for the response functions range from 3% to 6% for irrigated yields and 2% to 8% for irrigated water withdrawal. Further in- and out-of-sample validation exercises confirm that the statistical emulators are able to replicate the crop models’ spatial patterns of irrigated crop yields and irrigation water withdrawals, both in levels and in terms of changes over time, although accuracy varies by model and by region. The emulators estimated in this study therefore provide a reliable and computationally efficient alternative to global gridded crop yield models.
(Location: IWMI HQ Call no: e-copy only Record No: H049675)
(8.75 MB)
Evaluation of water resources systems and implementation of appropriate management strategies requires accurate and well classified information describing supply, demand, and consumption. The WA+ water accounting framework is a relevant tool in this regard. Earlier applications of the WA+ framework draw heavily from remote sensing (RS) data; however, applying RS data limits the application of the framework to past and current situations. Such analyses are needed for future assessments due to new management and climate scenarios. Therefore, the objective of this research is to link WA+ with the Soil Water Assessment Tool (SWAT) model to enhance it and to evaluate water management strategies through an integrated framework. The resulting system, SWAT-FARS (customized version of SWAT model for Fars region) is capable of supporting macro and micro water planning through a systematic presentation of the past trends, current and future status in water supply and demand. To explore this methodology, the system was applied to the Tashk-Bakhtegan basin (Iran). The trends in supply and consumption within the basin and some of the water saving policies that are mandated by the country’s 6th development plan were evaluated. Application of SWAT-FARS to the Task-Bakhtegan basin showed decrease in “Manageable water” of about 23% and a simultaneous increase of “Incremental irrigation” of about 53%; this lack of accessible water and imbalance of manageable water and water usage has almost omitted the basin’s “Outflows”. To alleviate pressures on the basin’s water resources, a suggested elimination of rice cultivation and improving pressurized irrigation showed the first policy could reduce water consumption by 0.08 BCM/yr and the second one can even increase water consumption by 0.25 BCM/yr over current conditions. The methodology used to develop SWAT-FARS is strongly recommended for other regions suffering water scarcity.
(Location: IWMI HQ Call no: e-copy only Record No: H049749)
(2.11 MB) (2.11 MB)
Integration of remote sensing data sets from multiple satellites is tested to simulate water storage variation of Lake Ziway, Ethiopia for the period 2009-2018. Sixty Landsat ETM+/OLI images served to trace temporal variation of lake surface area using a water extraction index. Time series of lake levels were acquired from two altimetry databases that were validated by in-situ lake level measurements. Coinciding pairs of optical satellite based lake surface area and radar altimetry based lake levels were related through regression and served for simulating lake storage variation. Indices for extracting lake surface area from images showed 91–99 % overall accuracy. Lake water levels from the altimetry products well agreed to in-situ lake level measurements with R2 = 0.92 and root mean square error of 11.9 cm. Based on this study we conclude that integrating satellite imagery and radar altimetry is a viable approach for frequent and accurate monitoring of lake water volume variation and for long-term change detection. Findings indicate water level reduction (4 cm/annum), surface area shrinkage (0.08km2 /annum) and water storage loss (20.4Mm3 /annum) of Lake Ziway (2009–2018).
(Location: IWMI HQ Call no: e-copy only Record No: H049925)
(2.35 MB)
This paper studies the conflict between economic and environmental sustainability objectives faced by a water agency when she allocates water quotas to farmers. This conflict consists in a water allocation problem between the amount of water claimed by farmers to irrigate their crops and the water flows needed for the conservation and the preservation of the ecosystems. This conflict in objectives is analysed in a dynamic hydro-economic model in discrete-time using the viability approach. The viability kernel that defines the states of the resource yielding intertemporal feasible paths able to satisfy the set of constraints over time is analytically identified. The associated set of viable quota policies and the trade-off between food production and ecosystem conservation objectives are characterized. The theoretical results of the paper are illustrated with numerical simulations based on the Western La Mancha aquifer in Spain.
(Location: IWMI HQ Call no: e-copy only Record No: H050122)
(1.12 MB)
Data exchange in transboundary waters is fundamental to advance cooperative water management. Nonetheless, the degree to which data are shared is not well understood. To gauge this degree, an assessment framework was developed and applied in 25 international river basins. The framework captures the degree to which a set of data parameters is exchanged among countries. A reasonable proportion of surveyed basins exchange some data, but the breadth of such exchange is often limited, and not regular. This paper highlights where data exchange can be improved and provides guidance on how indicators used in global assessment frameworks can motivate this improvement.
(Location: IWMI HQ Call no: e-copy only Record No: H050073)
(2.45 MB)
(Location: IWMI HQ Call no: e-copy only Record No: H050094)
(3.28 MB) (3.28 MB)
Groundwater use affects groundwater storage continuously as the removal of water changes both short-term and long-term groundwater level variation. This has implications for groundwater droughts, i.e. a below-normal groundwater level. The impact of groundwater use on groundwater droughts, however, remains unknown. Hence, the aim of this study is to investigate the impact of groundwater use on groundwater droughts in the absence of actual abstraction data. We present a methodological framework that consists of two approaches. The first approach compared groundwater droughts at monitoring sites that are potentially influenced by abstraction to groundwater droughts at sites that are known to be near natural. Observed groundwater droughts were compared in terms of drought occurrence, duration, and magnitude. The second approach investigated long-term trends in groundwater levels in all monitoring wells. This framework was applied to a case study of the UK, using four regional water management units in which groundwater levels are monitored and abstractions are licensed. Results show two asymmetric responses in groundwater drought characteristics due to groundwater use. The first response is an increase in shorter drought events and is found in three water management units where long-term annual average groundwater abstractions are smaller than recharge. The second response, observed in one water management unit where groundwater abstractions temporarily exceeded recharge, is a lengthening and intensification of groundwater droughts. Analysis of long-term (1984–2014) trends in groundwater levels shows mixed but generally positive trends, while trends in precipitation and potential evapotranspiration are not significant. The overall rising groundwater levels are consistent with changes in water use regulations and with a general reduction in abstractions during the period of investigation. We summarised our results in a conceptual typology that illustrates the asymmetric impact of groundwater use on groundwater drought occurrence, duration, and magnitude. The long-term balance between groundwater abstraction and recharge plays an important role in this asymmetric impact, which highlights the relation between short-term and long-term sustainable groundwater use.
(Location: IWMI HQ Call no: e-copy only Record No: H050143)
(5.44 MB) (5.44 MB)
Thirty-eight aquifer units are shared between Malawi and its neighbouring countries. It is essential to prioritize those transboundary aquifers that require immediate attention. A methodology of identifying hotspots in the transboundary aquifers of Malawi that may be at risk of depletion or contamination has been developed. There are 11 local-scale and three national-scale hotspots of transboundary concern in Malawi. Fiscal and planning measures can now be taken to assess these areas in more detail, fostering transboundary cooperation between stakeholders at both local and national scales.
13 Lapworth, D. J.; Dochartaigh, B. O.; Nair, T.; O'Keeffe, J.; Krishan, G.; MacDonald, A. M.; Khan, M.; Kelkar, N.; Choudhary, S.; Krishnaswamy, J.; Jackson, C. R. 2021. Characterising groundwater-surface water connectivity in the Lower Gandak Catchment, a barrage regulated biodiversity hotspot in the mid-Gangetic Basin. Journal of Hydrology, 594:125923. (Online first) [doi: https://doi.org/10.1016/j.jhydrol.2020.125923]
(Location: IWMI HQ Call no: e-copy only Record No: H050154)
(13.00 MB)
The alluvial aquifer system of the Indo-Gangetic Basin (IGB) is one of the world’s most important freshwater resources, sustaining humans and river ecosystems. Understanding groundwater recharge processes and connections to meteoric and surface water is necessary for effective water resource management for human and wider ecological requirements. Parts of the mid-Gangetic Basin, across eastern Uttar Pradesh and Bihar, are characterised by stable long-term groundwater levels, high annual rainfall, and limited historical groundwater use compared to parts of Northwest India for example. In this paper we use a combination of environmental tracers and hydrograph observations to characterise sources of recharge and groundwater-surface water interaction using a transect approach across the catchment of the River Gandak, a major barrage-regulated tributary of the River Ganga. Stable isotope results show that the dominant source of groundwater recharge, in the shallow (0–40 m bgl) Holocene and underlying Pleistocene aquifer system (>40 m bgl), is local rainfall. The shallow Holocene aquifer is also supplemented by local recharge from river and canal seepage and irrigation return flow in the upper and mid parts of the catchment. These observations are corroborated by evidence from detailed groundwater hydrographs and salinity observations, indicating localised canal, river and lake connectivity to groundwater. In the middle and lower catchment, river discharge is dominated by groundwater baseflow during the peak dry season when barrage gates are closed, which contributes to ecological flows for endangered river dolphins and gharial crocodiles. Groundwater residence time tracers indicate active modern recharge in the shallow alluvial aquifer system across the catchment. In the shallow Holocene aquifer elevated arsenic (As), iron (Fe), and manganese (Mn) exceeded WHO drinking water guidelines in a minority of sites, and uranium (U) and fluoride (F) concentrations approach but do not exceed the WHO guideline values. These observations varied across the catchment with higher As, Fe and Mn in the upper and mid catchments and higher U in the lower catchment. Groundwater salinity was typically between 500 and 1000 µS/cm, and isolated higher salinity was due to recharge from flood-plain wetlands and lakes impacted by evaporation. At present, the Gandak catchment has relatively high rainfall and low abstraction, which maintains stable groundwater levels and thus baseflow to the river in the dry season. Potential future threats to groundwater resources, and therefore river ecology due to the sensitivity to changes in baseflow in the catchment, would likely be driven by reductions in local monsoon rainfall, changes in water management practices and increased groundwater use.
14 Malakar, P.; Mukherjee, A.; Bhanja, S. N.; Ganguly, A. R.; Ray, R. K.; Zahid, A.; Sarkar, S.; Saha, D.; Chattopadhyay, S. 2021. Three decades of depth-dependent groundwater response to climate variability and human regime in the transboundary Indus-Ganges-Brahmaputra-Meghna mega river basin aquifers. Advances in Water Resources, 149:103856. [doi: https://doi.org/10.1016/j.advwatres.2021.103856]
(Location: IWMI HQ Call no: e-copy only Record No: H050254)
(3.12 MB)
Groundwater plays a major role in human adaptation and ecological sustainability against climate variability by providing global water and food security. In the Indus-Ganges-Brahmaputra-Meghna aquifers (IGBM), groundwater abstraction has been reported to be one of the primary contributors to groundwater storage variability. However, there is still a lack of understanding on the relative influence of climate and abstraction on groundwater. Data-guided statistical studies are reported to be crucial in understanding the human-natural complex system. Here, we attributed the long-term (1985–2015) impact of local-precipitation, global-climate cycles, and human influence on multi-depth groundwater levels (n=6753) in the IGBM using lag correlation analysis, wavelet coherence analysis, and regression-based dominance analysis. Our findings highlight the variable patterns of phase lags observed between multi-depth groundwater levels and precipitation depending on the different nature of climatic and anthropogenic drivers in different parts of the basin. We observed intuitive responses, i.e., rapid response in shallow groundwater and relatively delayed responses to the global climate patterns with increasing depth. However, in the most exploited areas, the hydrological processes governing the groundwater recharge are overwhelmed by unsustainable groundwater abstraction, thus decoupling the hydro-climatic continuum. Our results also suggest groundwater abstraction to be the dominant influence in most of the basin, particularly at the greater depth of the aquifer, thus highlighting the importance of understanding multi-depth groundwater dynamics for future groundwater management and policy interventions.
(Location: IWMI HQ Call no: e-copy only Record No: H050220)
(5.73 MB) (5.73 MB)
Context: Participatory modeling approaches provide opportunities for collective action responding to challenges of community resource limitations. In the context of climate change, challenges arise from the potential limi_tations of water availability and resulting conflicts within the agricultural sector. Northeast Lower Saxony is the region with the highest irrigation intensity in Germany due to the sandy soils with low water holding capacity, the cultivation of crops with high water demand, and a negative climatic water balance during the summer months. Water resources will become more limited as a consequence of climate change. Simultaneously, the irrigation demand will most likely increase due to intensified crop cultivation.
Objective: Responding to these challenges, we developed a novel method to identify leverage points for effective climate change adaptation measures. We applied this method to analyze opportunities for climate change adaptation within the agricultural sector in Northeast Lower Saxony. Furthermore, we assessed the potential of stakeholders to implement adaptation measures that correspond to the identified leverage points on different time scales.
Methods: Our leverage point analysis is based on a qualitative system dynamics model that was developed within a participatory modeling framework. We analyzed parameters, feedback loops, and typical system archetypes within the model. Leverage points that were related to the design and the intent of the model emerged during the iterative model building process. Subsequently, we introduced a rating system to evaluate the potential of each leverage point to be successful as a climate change adaptation measure. We provide a point-by-point analysis of the potential of key stakeholders to implement adaptation measures.
Results and conclusions: The leverage points analysis was applied to the case study of Northeast Lower Saxony. It revealed that collective action is needed to cope with these challenges. Decision-makers should provide financial incentives to increase water retention in the region. Farmers will have to improve irrigation efficiency and technology for crop production. Increased societal awareness of climate change-related water shortages has the potential to direct the system towards more sustainable water use and consumption patterns.
Significance: Our novel and structured approach is an attempt to analyze complex socio-economic systems. It supports mediating water resource conflicts between various stakeholders to facilitate collective action for adaptive planning.
(Location: IWMI HQ Call no: e-copy only Record No: H050319)
(5.81 MB) (5.81 MB)
This paper addresses the questions of acceptable upper limits for storage development and how best to deploy storage capacity in the long-term planning of built surface water storage in river basins. Storage-yield curves are used to establish sustainable storage development pathways and limits for a basin under a range of environmental flow release scenarios. Optimal storage distribution at a sub-basin level, which complies with an identified storage development pathway, can also be estimated. Two new indices are introduced—Water Supply Sustainability and Environmental Flow Sustainability—to help decide which pathways and management strategies are the most appropriate for a basin. Average pathways and conservative and maximum storage limits are illustrated for two example basins. Conservative and maximum withdrawal limits from storage are in the range of 45–50% and 60–65% of the mean annual runoff. The approach can compare the current level of basin storage with an identified pathway and indicate which parts of a basin are over- or under-exploited. A global storage–yield–reliability relationship may also be developed using statistics of annual basin precipitation to facilitate water resource planning in ungauged basins.
(Location: IWMI HQ Call no: e-copy only Record No: H050288)
(11.70 MB)
Water-saving technologies have long been seen as an effective method to reduce irrigation water use and alleviate regional water shortage. However, growing reports of more severe water shortage and increasing application of water-saving technologies across the world have necessitated reassessment of agricultural water-saving. This study develops a simple method based on satellite-based ET partitions to estimate water withdrawal, water consumption and return flow from the 1980s to 2010s, and quantifies water-savings across globe and four hot-spot irrigated areas at both field and regional scales based on water accounting framework. The results show that global irrigation water flows keep increasing from the 1980s to 2010s, with over 50% increase from the expansion in irrigated lands. While water-saving technologies are found mainly applied in originally old irrigated lands, traditional flooding irrigation is still dominant in newly-developed irrigated lands. Non-beneficial water consumption (soil evaporation) is effectively reduced by water-saving technologies, but return flow has increased at the same time. At field scale, water-saving technologies fail to save water because the accumulated increased return flow is more than the accumulated decreased non-beneficial water consumption. At regional scale, however, water is saved because the return flow percolated to fresh aquifers is seen as beneficial rather than loss. At the same time, the accumulated increase of beneficial water consumption (crop transpiration) exceeds regional water savings, which explains the paradox between wide application of water-saving technologies and more severe regional water shortage. This study provides key new evidence for the paradox of irrigation efficiency and helps reconsidering water-saving technologies and their impacts on regional water resources.
(Location: IWMI HQ Call no: e-copy only Record No: H050289)
(0.95 MB)
We study groundwater management under a regime shock affecting water availability, using a dynamic common-property resource game. The different players correspond to different groundwater uses (irrigation or urban water supply), enabling us to consider competition between economic sectors for the stock with limited availability. The players have different water demand functions and, under certain circumstances depending on the shock, different discount rates. The effects of asymmetries in both demand and discount rates are analyzed, comparing cooperative and non-cooperative solutions. A numerical analysis for the particular case of the Western La Mancha aquifer in Spain is conducted to analyze the degree of inefficiency of non-cooperative solutions with respect to cooperative solutions in terms of welfare. We show that a higher asymmetry in discount rates reduces the inefficiency of non-cooperative solutions. The opposite result is obtained when considering the asymmetry in demand.
(Location: IWMI HQ Call no: e-copy only Record No: H050373)
(1.71 MB) (1.71 MB)
In semi-arid India, managed aquifer recharge (MAR) is often used to enhance aquifer storage, and by implication, water security, and climate resilience, by capturing surface runoff, mainly through check dams implemented at the community level. Despite their extensive use, the design of these structures typically does not follow a systematic method to maximize performance. To aid in the improvement of check dam design parameters and location siting, we develop a dynamic tool, which integrates the daily water balance of a check dam with analytical infiltration equations to assess check dam performance measured as temporal dynamics of storage, infiltration, and evaporation. The tool is implemented in R environment and requires meteorological and hydrogeological data, as well as check dam geometry and nearby well-abstractions, if any. The tool is applied to a case study in Saurashtra in Gujarat, where field visits were conducted. Simulations show that typical check dams in the area are able to store a volume between three and seven times their storage capacity annually. Infiltration volumes highly depend on hydroclimatic and hydrogeological conditions, as well as the formation of a clogging layer, highlighting the importance of site selection and periodic maintenance. The tool is validated with data from a previous study in Rajasthan, where daily water balance parameters were monitored. Validation results show an average R 2 of 0.93 between the simulated and measured water levels. The results are adequate to suggest that the tool is able to assist in check dam planning in semi-arid environments.
20 Mamo, S.; Birhanu, B.; Ayenew, T.; Taye, G. 2021. Three-dimensional groundwater flow modeling to assess the impacts of the increase in abstraction and recharge reduction on the groundwater, groundwater availability and groundwater-surface waters interaction: a case of the Rib Catchment in the Lake Tana sub-basin of the Upper Blue Nile River, Ethiopia. Journal of Hydrology: Regional Studies, 35:100831. [doi: https://doi.org/10.1016/j.ejrh.2021.100831]
(Location: IWMI HQ Call no: e-copy only Record No: H050509)
(7.52 MB) (7.52 MB)
Study region: Rib catchment in the Lake Tana sub-basin, Upper Blue Nile River, Ethiopia.
Study focus: This paper aimed to assess the impacts of future increase in abstraction and recharge reduction on the groundwater, groundwater availability, and groundwater-surface waters interaction based on a three-dimensional groundwater flow modeling. Calibration was made under the steady state condition. Scenario analysis performed for 1) increase in abstraction, 2) decrease in recharge, 3) the worst-case scenario that combined the aforementioned two scenarios and with additional extraction for irrigation, and 4) for the optimal-case scenario, which considers 5% recharge increase for the worst-case scenario model.
New hydrological insights for the region: It is found that the groundwater flows from uplands toward the Tana Lake. The total inflow to and outflow from the system in the calibrated model are 1733480 m3/d and 1840451 m3/d, respectively. Groundwater level drop, reduction in base flows to surface waters, and in evapotranspiration flux compared to the calibrated values encountered for all scenarios, which are significant (mean 38.4 m, 28.5–100 %, and 97.8 %, respectively) for the worst-case scenario. On the other hand, an increase in groundwater level (mean 9.8 m), base flows (0–14.4 %), and evapotranspiration flux (29.5 %) observed for the optimal scenario when compared to the worst-case scenario results. Results suggest that groundwater management measures should be implemented to mitigate the impacts.
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