17 results found
Ochoa-Tocachi BF, Bardales JD, Antiporta J, et al., 2019, Potential contributions of pre-Inca infiltration infrastructure to Andean water security, Nature Sustainability, Vol: 2, Pages: 584-593, ISSN: 2398-9629
Water resources worldwide are under severe stress from increasing climate variability and human pressures. In the tropical Andes, pre-Inca cultures developed nature-based water harvesting technologies to manage drought risks under natural climatic extremes. While these technologies have gained renewed attention as a potential strategy to increase water security, limited scientific evidence exists about their potential hydrological contributions at catchment scale. Here, we evaluate a 1,400-year-old indigenous infiltration enhancement system that diverts water from headwater streams onto mountain slopes during the wet season to enhance the yield and longevity of downslope natural springs. Infiltrated water is retained for an average of 45 d before resurfacing, confirming the system’s ability to contribute to dry-season flows. We estimate that upscaling the system to the source-water areas of the city of Lima can potentially delay 99 × 106 m3 yr−1 of streamflow and increase dry-season flows by 7.5% on average, which may provide a critical complement to conventional engineering solutions for water security.
Uprety M, Ochoa-Tocachi BF, Paul JD, et al., 2019, Improving water resources management using participatory monitoring in a remote mountainous region of Nepal, Journal of Hydrology Regional Studies, Vol: 23, ISSN: 2214-5818
Study RegionWe interrogate the water resources of the Upper Kaligandaki River Basin (UKGRB), in the remote Mustang District of northwestern Nepal. The Nepal Himalayas are a major reservoir of freshwater; yet the impediments to its exploitation by local inhabitants are manifold, including weak governance structures, steep and irregular terrain, and frequent natural hazards that are linked to climate change. The UKGRB is characterised by its extreme fragility, paucity of water and water-related data, and enormous variability of the effects of climate change on glaciers through time and space.Study FocusThe purpose of this paper is to elucidate catchment hydrology and local flow variability, before demonstrating the ways in which sustainable water resource management (WRM) can be achieved regionally.New Hydrological Insights for the RegionWe present the local crop water balance, and suggest methods to reduce crop water requirements and to ensure a more equitable distribution of available seasonal flow. We also propose a series of long-term changes that are needed to secure sustainability. Then, we suggest that the principles of citizen science can help to improve the spatial coverage of data, generating new hydrological time series (e.g. river discharge), which can aid local decision makers in the WRM realm (e.g. irrigation scheduling). This approach has the potential to be scaled-up across the entire UKGRB (and, indeed, Nepal as a whole).
Regmi S, Bhusal J, Gurung P, et al., Learning to cope with water variability through participatory monitoring: the case study of the Mountainous region, Nepal, Meteorology Hydrology and Water Management, Vol: 7, Pages: 49-61, ISSN: 2299-3835
Participatory monitoring allows communities to understand the use and management of local water resources and at the same time develop a sense of ownership of environmental information. The data generated through participatory monitoring of stream flow and rainfall generate evidences to corroborate local people's experiences with changing water resources patterns. In this study we evaluate the potential of participatory monitoring of hydrological variables to improve scarce water supply utilization in agriculture. The case study site is the Mustang district in Nepal, which is located in the upper Kaligandaki river basin in the Himalayas with unique and complex geographical and climatic features. This region is characterized by a semi-arid climate with total annual precipitation of less than 300 mm. Water supply, agricultural land, and livestock grazing are the key ecosystem services that underpin livelihood security of the local population, particularly socio-economically vulnerable groups. An analysis of the measured stream flow data indicate that annual flow of water in the stream can meet the current crop irrigation water needs for the agricultural land of the research site. The data provide local farmers a new way of understanding local water needs. Participatory monitoring would contribute to an optimization of the use of ecosystem services to support economic development and livelihood improvement.
Bonnesoeur V, Locatelli B, Ochoa Tocachi B, 2019, Impactos de la Forestación en el Agua y los Suelos de los Andes: ¿Qué sabemos?, Lima, Peru, Publisher: Forest Trends
RESUMEN DE POLÍTICAS: Este documento resume los resultados de una revisión sistemática sobre los impactos de la forestación en el agua y los suelos en los Andes (detallados en Bonnesoeur et al., 2019). Para cada resultado, reportamos el nivel de confianza en la evidencia encontrada en la literatura revisada. La forestación impacta sobre la disponibilidad de agua, la regulación hidrológica, y la erosión del suelo. Los resultados de esta síntesis también ayudaron a identificar vacíos de conocimiento, los cuales se describen al final.
Bonnesoeur V, Locatelli B, Guariguata MR, et al., 2019, Impacts of forests and forestation on hydrological services in the Andes: A systematic review, Forest Ecology and Management, Vol: 433, Pages: 569-584, ISSN: 0378-1127
Several Andean countries have planned to restore forest cover in degraded land to enhance the provision of multiple ecosystem services in response to international commitments such as the Bonn Challenge. Hydrological services, e.g. water supply, hydrological regulation and erosion mitigation, are particularly important to sustain the life of more than fifty million Andean people. While rapid and important forest cover changes have occurred during recent decades, critical information on the impact of forestation on hydrological services has not yet been synthesized in the context of Andean ecosystems. We define forestation as the establishment of forest by plantation or natural regeneration on areas that either had forest in the past or not. To help improve decision-making on forestation in the Andes, we reviewed the available literature concerning the impacts of forestation on water supply, hydrological regulation and mitigation of erosion and landslides. We also examined available data on the most relevant hydrological processes such as infiltration, evapotranspiration and runoff in forest stands. Hydrological services from native forests were also included as a reference state for comparing processes and services provided by forestation. Following systematic review protocols, we synthesized 155 studies using different methods, including meta-analyses and meta-regressions. Results show that forestation has had clear impacts on degraded soils, through reducing water erosion of soils and risk of moderate floods, increasing soil infiltration rate by 8 and topsoil organic matter (SOM). We found that 20 years of tree plantation was sufficient to recover infiltration rate and sediment yield close to the levels of native forests whereas SOM, soil water storage and surface runoff of native forests could not be recovered by forestation in the time scales examined. The benefits in terms of hydrological regulation are at the expense of a reduction in total water supply since
Ochoa-Tocachi B, Alemie T, Guzman CD, et al., 2019, Sensitivity analysis of the parameter-efficient distributed (PED) model for discharge and sediment concentration estimation in degraded humid landscapes, Land Degradation and Development, Vol: 30, Pages: 151-165, ISSN: 1085-3278
Sustainable development in degraded landscapes in the humid tropics require effective soil and water management practices. Coupled hydrological‐erosion models have been used to understand and predict the underlying processes at watershed scale and the effect of human interventions. One prominent tool is the parameter‐efficient distributed (PED) model, which improves on other models by considering a saturation‐excess runoff generation driving erosion and sediment transport in humid climates. This model has been widely applied at different scales for the humid monsoonal climate of the Ethiopian Highlands, with good success in estimating discharge and sediment concentrations. However, previous studies performed manual calibration of the involved parameters without reporting sensitivity analyses or assessing equifinality. The aim of this article is to provide a multi‐objective global sensitivity analysis of the PED model using automatic random sampling implemented in the SAFE Toolbox. We find that relative parameter sensitivity depends greatly on the purpose of model application and the outcomes used for its evaluation. Five of the 13 PED model parameters are insensitive for improving model performance. Additionally, associating behavioural parameter values with a clear physical meaning provides slightly better results and helps interpretation. Lastly, good performance in one module does not translate directly into good performance in the other module. We interpret these results in terms of the represented hydrological and erosion processes and recommend field data to inform model calibration and validation, potentially improving land degradation understanding and prediction and supporting decision‐making for soil and water conservation strategies in degraded humid landscapes.
Zogheib C, Ochoa-Tocachi BF, Paul JD, et al., 2018, Exploring a water data, evidence, and governance theory, Water Security, Vol: 4-5, Pages: 19-25, ISSN: 2468-3124
The hydrological evidence on which water resource management and broader governance decisions are based is often very limited. This issue is especially pronounced in lower- and middle-income countries, where not only data are scarce but where pressure on water resources is often already very high and increasing. Historically, several governance theories have been put forward to examine water resource management. One of the more influential is Elinor Ostrom’s theory of common-pool resources. However while used very widely, the underlying principles of Ostrom’s approach make pronounced implicit assumptions about the role of data and evidence in common-pool resource systems. We argue here this overlooks how power relations, user characteristics, system arrangements, and technological advances modulate fundamental associations between data, evidence, and governance, which we contend need to be considered explicitly. Examining the case of water allocations in Quito, Ecuador, we develop a set of concrete criteria to inform the ways in which Ostrom’s principles can be applied in a data-scarce, institutionally complex, polycentric context. By highlighting the variable impact of data availability on subsequent evidence generation, these criteria have the potential to test the applicability of common assumptions about how to achieve water security in a developmental context, and hence offer the possibility of developing a more encompassing theory about the interactions between water data, evidence, and governance.
Bonnesoeur V, Locatelli B, Ochoa Tocachi B, 2018, Impacts of forestation on water and soils in the Andes: What do we know?, Info Brief, Bogor, Indonesia, Publisher: Center for International Forestry Research (CIFOR)
POLICY BRIEF: This brief summarizes the findings of a systematic review on the impacts of forestation on water and soils in the Andes (detailed in Bonnesoeur et al., 2019). For each finding, we report the confidence level in the evidence found in the literature reviewed. Forestation impacts on water supply, hydrological regulation and soil erosion. The results of the synthesis also helped identify research gaps, which are described at the end.
Ochoa-Tocachi BF, Buytaert W, Antiporta J, et al., 2018, High-resolution hydrometeorological data from a network of headwater catchments in the tropical Andes, Scientific Data, Vol: 5, ISSN: 2052-4463
This article presents a hydrometeorological dataset from a network of paired instrumented catchments, obtained by participatory monitoring through a partnership of academic and non-governmental institutions. The network consists of 28 headwater catchments (<20 km2) covering three major biomes in 9 locations of the tropical Andes. The data consist of precipitation event records at 0.254 mm resolution or finer, water level and streamflow time series at 5 min intervals, data aggregations at hourly and daily scale, a set of hydrological indices derived from the daily time series, and catchment physiographic descriptors. The catchment network is designed to characterise the impacts of land-use and watershed interventions on the catchment hydrological response, with each catchment representing a typical land use and land cover practice within its location. As such, it aims to support evidence-based decision making on land management, in particular evaluating the effectiveness of catchment interventions, for which hydrometeorological data scarcity is a major bottleneck. The data will also be useful for broader research on Andean ecosystems, and their hydrology and meteorology.
Buytaert W, Ochoa Tocachi B, Hannah DM, et al., 2018, Co-generating knowledge on ecosystem services and the role of new technologies, Ecosystem Services and Poverty Alleviation: Trade-offs and Governance, Editors: Schreckenberg, Mace, Poudyal, London, Publisher: Taylor & Francis Group, Pages: 174-188, ISBN: 9780429016295
Policy makers are increasingly aware that decision-making in the context of ecosystem services management, and of development, can benefit from collaborative and inclusive approaches to knowledge generation and the design of intervention strategies, such as by providing a more prominent role for indigenous knowledge in decision-making and by using participatory methods for data collection and knowledge generation. In this chapter, we discuss how technologies such as mobile phones, low-cost and robust sensors, and increasingly pervasive remote-sensing satellites and drones can be particularly transformative in the way they facilitate the creation, access and transmission of information about ecosystem services, and support evidence-based decision-making. Furthermore, we discuss how these technologies can be used to promote stakeholder involvement in the knowledge generation process and to make it more inclusive and participatory. While we highlight potential risks related to the use of new technologies, such as exploitation by specific stakeholders to support specific agendas or interests, we identify opportunities for an increasing diversification and tailoring of knowledge creation, moving away from a top-down process dominated by scientists and toward more decentralised, bottom-up and iterative approaches that can have a transformative impact on local ecosystem services management, making it more inclusive, polycentric, evidence-based and robust.
Ochoa-Tocachi BF, Buytaert W, De Bièvre B, 2018, Participatory Monitoring of the Impact of Watershed Interventions in the Tropical Andes, Andean Hydrology, Publisher: CRC Press, Pages: 127-156
Ochoa Tocachi BF, Buytaert W, De Bièvre B, 2017, Participatory monitoring of the impact of watershed interventions in the tropical Andes, Andean Hydrology, Editors: Rivera, Godoy-Faundez, Lillo Saavedra, Publisher: CRC Press (Taylor & Francis Group), Pages: 126-163, ISBN: 9781498788403
This chapter documents the motivations and methods of the Regional Initiative for Hydrological Monitoring of Andean Ecosystems (iMHEA). First, it introduces the context that led to the formation of a diverse consortium of institutions with a joint interest in Andean ecosystems and water. The methodological approach adopted by the monitoring network is then presented in detail. Lastly, this chapter shows preliminary main results, the most relevant milestones and breakthroughs, and the major remaining challenges and perspectives in the scientific, technological and social domains. The objective of the monitoring, as promoted by iMHEA, is to generate standardized data that can be used to increase the knowledge about hydrological ecosystem services in Andean watersheds and the impacts of watershed interventions. The correct use of the generated knowledge, from community level to national governance entities, proves crucial to increase catchment intervention efficiency and improve decision-making on water resources management in data-scarce regions, with potential application to other regions of the world.
Manz B, Paez-Bimos S, Horna N, et al., 2017, Comparative Ground Validation of IMERG and TMPA at Variable Spatiotemporal Scales in the Tropical Andes, Journal of Hydrometeorology, Vol: Sept 2017, Pages: 2469-2489, ISSN: 1525-7541
An initial ground validation of the Integrated Multisatellite Retrievals for GPM (IMERG) Day-1 product from March 2014 to August 2015 is presented for the tropical Andes. IMERG was evaluated along with the Tropical Rainfall Measuring Mission (TRMM) Multisatellite Precipitation Analysis (TMPA) against 302 quality-controlled rain gauges across Ecuador and Peru. Detection, quantitative estimation statistics, and probability distribution functions are calculated at different spatial (0.1°, 0.25°) and temporal (1 h, 3 h, daily) scales. Precipitation products are analyzed for hydrometeorologically distinct subregions. Results show that IMERG has a superior detection and quantitative rainfall intensity estimation ability than TMPA, particularly in the high Andes. Despite slightly weaker agreement of mean rainfall fields, IMERG shows better characterization of gauge observations when separating rainfall detection and rainfall rate estimation. At corresponding space–time scales, IMERG shows better estimation of gauge rainfall probability distributions than TMPA. However, IMERG shows no improvement in both rainfall detection and rainfall rate estimation along the dry Peruvian coastline, where major random and systematic errors persist. Further research is required to identify which rainfall intensities are missed or falsely detected and how errors can be attributed to specific satellite sensor retrievals. The satellite–gauge difference was associated with the point-area difference in spatial support between gauges and satellite precipitation products, particularly in areas with low and irregular gauge network coverage. Future satellite–gauge evaluations need to identify such locations and investigate more closely interpixel point-area differences before attributing uncertainties to satellite products.
Ochoa-Tocachi B, Buytaert W, De Bièvre B, 2016, Regionalization of land-use impacts on streamflow using a network of paired catchments, Water Resources Research, Vol: 52, Pages: 6710-6729, ISSN: 1944-7973
Quantifying the impact of land use and cover (LUC) change on catchment hydrological response is essential for land-use planning and management. Yet hydrologists are often not able to present consistent and reliable evidence to support such decision-making. The issue tends to be twofold: a scarcity of relevant observations, and the difficulty of regionalizing any existing observations. This study explores the potential of a paired catchment monitoring network to provide statistically robust, regionalized predictions of LUC change impact in an environment of high hydrological variability. We test the importance of LUC variables to explain hydrological responses and to improve regionalized predictions using 24 catchments distributed along the Tropical Andes. For this, we calculate first 50 physical catchment properties, and then select a subset based on correlation analysis. The reduced set is subsequently used to regionalize a selection of hydrological indices using multiple linear regression. Contrary to earlier studies, we find that incorporating LUC variables in the regional model structures increases significantly regression performance and predictive capacity for 66% of the indices. For the runoff ratio, baseflow index, and slope of the flow duration curve, the mean absolute error reduces by 53% and the variance of the residuals by 79%, on average. We attribute the explanatory capacity of LUC in the regional model to the pairwise monitoring setup, which increases the contrast of the land-use signal in the data set. As such, it may be a useful strategy to optimize data collection to support watershed management practices and improve decision-making in data-scarce regions.
Ochoa-Tocachi B, Buytaert W, De Bièvre B, et al., 2016, Impacts of land use on the hydrological response of tropical Andean catchments, Hydrological Processes, Vol: 30, Pages: 4074-4089, ISSN: 1099-1085
Changes in land use and land cover are major drivers of hydrological alteration in the tropical Andes. However, quantifying their impacts is fraught with difficulties because of the extreme diversity in meteorological boundary conditions, which contrasts strongly with the lack of knowledge about local hydrological processes. Although local studies have reduced data scarcity in certain regions, the complexity of the tropical Andes poses a big challenge to regional hydrological prediction.This study analyses data generated from a participatory monitoring network of 25 headwater catchments covering three of the major Andean biomes (páramo, jalca, and puna), and link their hydrological responses to main types of human interventions (cultivation, afforestation and grazing). A paired catchment setup was implemented to evaluate the impacts of change using a “trading space-for-time” approach. Catchments were selected based on regional representativeness and contrasting land use types. Precipitation and discharge have been monitored and analysed at high temporal resolution for a time period between 1 and 5 years.The observed catchment responses clearly reflect the extraordinarily wide spectrum of hydrological processes of the tropical Andes. They range from perennially humid páramos in Ecuador and northern Peru with extremely large specific discharge and baseflows, to highly seasonal, flashy catchments in the drier punas of southern Peru and Bolivia. The impacts of land use are similarly diverse and their magnitudes are a function of catchment properties, original and replacement vegetation, and management type. Cultivation and afforestation consistently affect the entire range of discharges, particularly low flows. The impacts of grazing are more variable, but have the largest effect on the catchment hydrological regulation. Overall, anthropogenic interventions result in increased streamflow variability and significant reductions in catchmen
Crespo P, Célleri R, Buytaert W, et al., 2013, Impactos del cambio de uso de la tierra sobre la hidrología de los páramos húmedos andinos, Avances en investigación para la conservación de los páramos andinos, Editors: Cuesta, Sevink, Llambí, De Bièvre, Posner, Publisher: Consorcio para el Desarrollo Sostenible de la Ecorregión Andina - CONDESAN, Pages: 287-304, ISBN: 978-612-45881-5-0
This paper presents a summarized compilation of the results of research performed in wet Andean paramo ecosystem in southern Ecuador using paired micro-catchments in order to study the land-use change impacts on its hydrology. The comparative analysis revealed that extensive livestock seems not to affect the hydrological response, primarily due to the low animal density, while the main impact of cultivation is the reduction in the regulation function of the catchment with a large increase in the magnitude of peak flows, a decrease of base flows, and, in general, a reduction of its buffering capacity. Moreover, a decrease in water yield, which is possibly caused by a higher evapotranspiration, is observed. On the other hand, pine plantations produce a decrease of annual water yield as a consequence of increased evapotranspiration. Furthermore, research results revealed that vertical infiltration through the soil is dominant under wet conditions, whereas preferential flow within the organic horizon to the underlying mineral horizon is dominant during low intensity rains. Only during long rain events saturated excess surface flow is observed; otherwise, near surface lateral flow in the organic layer occurs. Preliminary results show this water movement process in the subsoil is not affected by land-use change.
Llambí LD, Soto Werschitz A, Célleri R, et al., 2012, Ecología, Hidrología y Suelos del Páramo, Quito, Publisher: Monsalve Moreno
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