scholarly journals Hydrologic Analysis of an Intensively Irrigated Area in Southern Peru Using a Crop-Field Scale Framework

Water ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 318
Author(s):  
Xiaolu Wei ◽  
Pablo Garcia-Chevesich ◽  
Francisco Alejo ◽  
Vilma García ◽  
Gisella Martínez ◽  
...  
Keyword(s):  
Water Resources ◽  
Decision Makers ◽  
Scale Model ◽  
Substantial Contribution ◽  
Return Flow ◽  
Climate Change Scenarios ◽  
Field Scale ◽  
Southern Peru ◽  
Stream Discharge ◽  
Crop Field

Majes is one of the largest agricultural areas in the Arequipa region (southern Peru). Low seasonal precipitation and increasing water demands for agricultural irrigation, industry, and human consumption have made water supply projections a major concern. Agricultural development is becoming more extensive in this dry, sunny climate where crops can be grown year-round. However, because this type of project usually involves significant perturbations to the regional water cycle, understanding the effects of irrigation on local hydrology is crucial. Based on the watershed-scale Soil and Water Assessment Tool (SWAT), this investigation focuses on the impacts of intensive irrigation on hydrological responses in the Majes region. This study is unique because we allow for crop-field scale input within our regional-scale model to provide information at this smaller scale, which is important to inform local stakeholders and decision makers. Each hydrologic response unit (HRU) was generated to represent an individual crop field, so that management practices could be applied according to real-world scenarios. The management file of each HRU was modified to include different operation schedules for crop rotation, irrigation, harvest, and tillage. The model was calibrated and validated against monthly observed stream discharge during the 2009–2020 period. Additionally, evapotranspiration, irrigation water volume, and daily stream discharge downstream of the local river (Siguas) were used to verify the model performance. A total of 49 sub-basins and 4222 HRUs were created, with 3000 HRUs designated to represent individual crop fields. The simulation results revealed that infiltration from agricultural activities in Majes represents the majority of annual groundwater return flow, which makes a substantial contribution to streamflow downstream of the Siguas River. Simulations also suggested that groundwater flow processes and the interactions between surface and groundwater have a major impact on the water balance of the study area. Additionally, climate variability had a higher impact on surface runoff than on groundwater return flow, illustrating that the groundwater component in the study area is important for future water resources resiliency under expected climate change scenarios. Finally, there is a need to perform a follow-up implementation to provide a guideline for decision-makers to assess future sustainable water resources management under varying climatic conditions for this arid irrigated system.

Integrated basin-scale and field-scale modelling as a tool to assess improved water and salinity management

Soil Research ◽  
2004 ◽  
Vol 42 (4) ◽  
pp. 355 ◽  
Author(s):  
M. Torabi ◽  
H. R. Salemi ◽  
P. Droogers ◽  
M. Noshadi
Keyword(s):  
Water Resources ◽  
Scale Model ◽  
Water Quantity ◽  
Irrigation Season ◽  
Baseline Scenario ◽  
Field Scale ◽  
Scenario Analyses ◽  
Basin Scale ◽  
Return Flows ◽  
The Impact

This study was conducted to investigate the impact of changes in water management on water and salinity problems and crop production at field and basin level by analysing several probable scenarios. First, a simplified water and salinity basin model (WSBM) was developed for a quick analysis of river basin processes and was combined with the comprehensive field-scale model, SWAP (soil–water–atmosphere–plant). The WSBM model was calibrated and used for water resources analyses in Zayandeh Rud basin in central Iran. Observed and simulated stream flows were similar, proving that the model could be used for scenario analyses. Yield functions for cotton were developed with SWAP, including the impact of water quantity and quality on crop yields and field water and salinity balances. Three scenarios were considered. The first scenario analysed the effect of more efficient irrigation techniques on the basin water resources, where it was assumed that farmers would not accept lower water allocations if they invested in these more efficient techniques. Therefore, return flows would decrease and less water would be available for downstream users. It was concluded that the effect on the downstream irrigation schemes was dramatic, with a 22% decrease in yield. Obviously, upstream yields would increase. A second scenario was defined where the effect of an increase in water extraction for the town of Esfahan was evaluated. In terms of basin-scale water quantity aspects, this increased extraction was negligible as extractions were relatively low and return flows high. The last scenario was developed to study the additional releases required from the reservoir to provide sufficient water for expansion of the tail-end Rudasht irrigation scheme. If no restriction were imposed on water quality, additional releases from the reservoir would be limited. However, if salinity levels were not to exceed 2�dS/m, mean annual water release requirements from the reservoir would increase from 52 to 64 m3/s, and peak requirements during the irrigation season would increase from 85 to 112 m3/s. In this case, the crop yield would increase from 66% (for the baseline scenario) to 73%. Finally, it was concluded that the methodology and the models developed were useful for a swift and transparent analysis of past, current, and future water and salt resources, and to perform scenario analyses.

Soil Cleanup by In-Situ Aeration. XVII. Field-Scale Model with Distributed Diffusion

1994 ◽  
Vol 29 (10) ◽  
pp. 1251-1274 ◽  
Author(s):  
Céser Gómez-Lahoz ◽  
James M. Rodríguez-Maroto ◽  
David J. Wilson∗
Keyword(s):  
Scale Model ◽  
Field Scale ◽  
Soil Cleanup

scholarly journals Soil salinization under different climate change scenarios: A global scale analysis

2021 ◽  
Author(s):  
Nima Shokri ◽  
Amirhossein Hassani ◽  
Adisa Azapagic
Keyword(s):  
Climate Change ◽  
Water Resources ◽  
Soil Salinity ◽  
Global Scale ◽  
Soil Salinization ◽  
Water Evaporation ◽  
Climate Change Scenarios ◽  
Spatio Temporal ◽  
Salt Affected Soils

<p>Population growth and climate change is projected to increase the pressure on land and water resources, especially in arid and semi-arid regions. This pressure is expected to affect all driving mechanisms of soil salinization comprising alteration in soil hydrological balance, sea salt intrusion, wet/dry deposition of wind-born saline aerosols — leading to an increase in soil salinity. Soil salinity influences soil stability, bio-diversity, ecosystem functioning and soil water evaporation (1). It can be a long-term threat to agricultural activities and food security. To devise sustainable action plan investments and policy interventions, it is crucial to know when and where salt-affected soils occur. However, current estimates on spatio-temporal variability of salt-affected soils are majorly localized and future projections in response to climate change are rare. Using Machine Learning (ML) algorithms, we related the available measured soil salinity values (represented by electrical conductivity of the saturated paste soil extract, EC<sub>e</sub>) to some environmental information (or predictors including outputs of Global Circulation Models, soil, crop, topographic, climatic, vegetative, and landscape properties of the sampling locations) to develop a set of data-driven predictive tools to enable the spatio-temporal predictions of soil salinity. The outputs of these tools helped us to estimate the extent and severity of the soil salinity under current and future climatic patterns at different geographical levels and identify the salinization hotspots by the end of the 21<sup>st</sup> century in response to climate change. Our analysis suggests that a soil area of 11.73 Mkm<sup>2</sup> located in non-frigid zones has been salt-affected in at least three-fourths of the 1980 - 2018 period (2). At the country level, Brazil, Peru, Sudan, Colombia, and Namibia were estimated to have the highest rates of annual increase in the total area of soils with an EC<sub>e</sub> ≥ 4 dS m<sup>-1</sup>. Additionally, the results indicate that by the end of the 21<sup>st</sup> century, drylands of South America, southern and Western Australia, Mexico, southwest United States, and South Africa will be the salinization hotspots (compared to the 1961 - 1990 period). The results of this study could inform decision-making and contribute to attaining the United Nation’s Sustainable Development Goals for land and water resources management.</p><p>1. Shokri-Kuehni, S.M.S., Raaijmakers, B., Kurz, T., Or, D., Helmig, R., Shokri, N. (2020). Water Table Depth and Soil Salinization: From Pore-Scale Processes to Field-Scale Responses. Water Resour. Res., 56, e2019WR026707. https://doi.org/ 10.1029/2019WR026707</p><p>2. Hassani, A., Azapagic, A., Shokri, N. (2020). Predicting Long-term Dynamics of Soil Salinity and Sodicity on a Global Scale, Proc. Nat. Acad. Sci., 117, 52, 33017–33027. https://doi.org/10.1073/pnas.2013771117</p>

scholarly journals Evaluation of the implementation of IWRM in the lower Oueme valley, south Benin

2020 ◽  
Author(s):  
Fêmi Cocker ◽  
Jean-Bosco K. Vodounou ◽  
Jacob A. Yabi
Keyword(s):  
Water Resources ◽  
Integrated Water Resources Management ◽  
Efficiency Score ◽  
Decision Makers ◽  
The Sustainable Development ◽  
Efficient Management ◽  
Development Goals ◽  
Action Measures ◽  
Development And Management ◽  
Institutional Efficiency

Abstract The objective of this study is to assess the level of application of integrated water resources management (IWRM) in the lower Oueme valley. In order to achieve this, interviews with the actors' families allowed, on the basis of the survey on indicator 6.5.1 of the Sustainable Development Goals, to represent the degree of implementation of IWRM in the lower Oueme valley using a United Nations (UN) form. The results of this analysis reveal a low level of IWRM implementation with a score of 31 on a scale of 0–100. The weaknesses identified are mainly related to the lack of funding (score of 20/100) to cover all aspects of the development and management of water resources. Inadequate instruments or tools (score of 25/100) to enable decision-makers and users to make rational and informed decisions between different options and action measures, the unfavourable environment (score of 35/100) and finally weak institutional efficiency (score of 45/100), intersectoral coordination, and the involvement of various other stakeholders, are all evils that undermine the efficient management of water resources in the lower valley of Oueme.

scholarly journals A Hydrological Modeling Approach for Assessing the Impacts of Climate Change on Runoff Regimes in Slovakia

Water ◽  
2021 ◽  
Vol 13 (23) ◽  
pp. 3358
Author(s):  
Patrik Sleziak ◽  
Roman Výleta ◽  
Kamila Hlavčová ◽  
Michaela Danáčová ◽  
Milica Aleksić ◽  
...  
Keyword(s):  
Climate Change ◽  
Water Resources ◽  
Hydrological Modeling ◽  
Performance Metrics ◽  
Climate Change Scenarios ◽  
Reference Period ◽  
Changing Climate ◽  
Time Horizons ◽  
The Future

The changing climate is a concern with regard to sustainable water resources. Projections of the runoff in future climate conditions are needed for long-term planning of water resources and flood protection. In this study, we evaluate the possible climate change impacts on the runoff regime in eight selected basins located in the whole territory of Slovakia. The projected runoff in the basins studied for the reference period (1981–2010) and three future time horizons (2011–2040, 2041–2070, and 2071–2100) was simulated using the HBV (Hydrologiska Byråns Vattenbalansavdelning) bucket-type model (the TUW (Technische Universität Wien) model). A calibration strategy based on the selection of the most suitable decade in the observation period for the parameterization of the model was applied. The model was first calibrated using observations, and then was driven by the precipitation and air temperatures projected by the KNMI (Koninklijk Nederlands Meteorologisch Instituut) and MPI (Max Planck Institute) regional climate models (RCM) under the A1B emission scenario. The model’s performance metrics and a visual inspection showed that the simulated runoff using downscaled inputs from both RCM models for the reference period represents the simulated hydrological regimes well. An evaluation of the future, which was performed by considering the representative climate change scenarios, indicated that changes in the long-term runoff’s seasonality and extremality could be expected in the future. In the winter months, the runoff should increase, and decrease in the summer months compared to the reference period. The maximum annual daily runoff could be more extreme for the later time horizons (according to the KNMI scenario for 2071–2100). The results from this study could be useful for policymakers and river basin authorities for the optimum planning and management of water resources under a changing climate.

scholarly journals Contrasting climate change impact on river flows from high-altitude catchments in the Himalayan and Andes Mountains

2016 ◽  
Vol 113 (33) ◽  
pp. 9222-9227 ◽  
Author(s):  
Silvan Ragettli ◽  
Walter W. Immerzeel ◽  
Francesca Pellicciotti
Keyword(s):  
Climate Change ◽  
Water Resources ◽  
High Altitude ◽  
Water Availability ◽  
Climate Change Impact ◽  
River Flow ◽  
Climate Change Scenarios ◽  
Glacier Area ◽  
Spatiotemporal Resolution ◽  
Change Impact

Mountain ranges are the world’s natural water towers and provide water resources for millions of people. However, their hydrological balance and possible future changes in river flow remain poorly understood because of high meteorological variability, physical inaccessibility, and the complex interplay between climate, cryosphere, and hydrological processes. Here, we use a state-of-the art glacio-hydrological model informed by data from high-altitude observations and the latest climate change scenarios to quantify the climate change impact on water resources of two contrasting catchments vulnerable to changes in the cryosphere. The two study catchments are located in the Central Andes of Chile and in the Nepalese Himalaya in close vicinity of densely populated areas. Although both sites reveal a strong decrease in glacier area, they show a remarkably different hydrological response to projected climate change. In the Juncal catchment in Chile, runoff is likely to sharply decrease in the future and the runoff seasonality is sensitive to projected climatic changes. In the Langtang catchment in Nepal, future water availability is on the rise for decades to come with limited shifts between seasons. Owing to the high spatiotemporal resolution of the simulations and process complexity included in the modeling, the response times and the mechanisms underlying the variations in glacier area and river flow can be well constrained. The projections indicate that climate change adaptation in Central Chile should focus on dealing with a reduction in water availability, whereas in Nepal preparedness for flood extremes should be the policy priority.

Adsorption of water vapor by soil in semi arid ecosystems: reconciling estimates from Lysimeters and Eddy Covariance

2021 ◽  
Author(s):  
Sinikka Paulus ◽  
Tarek S. El-Madany ◽  
René Orth ◽  
Jacob A. Nelson ◽  
Anke Hildebrandt ◽  
...  
Keyword(s):  
Water Vapor ◽  
Soil Water ◽  
Eddy Covariance ◽  
Water Vapor Adsorption ◽  
Dry Season ◽  
Climate Change Scenarios ◽  
Field Scale ◽  
Vapor Adsorption ◽  
Semi Arid

<p>Current climate change scenarios project altered rainfall frequencies which boosts scientific interest in ecosystems' responses to prolonged dry conditions. Under less rainfall, NRWI may play an increasingly important role, Yet, only sparse data are available to assess the role of non-rainfall water input (NRWI) during times of low water availability across ecoregions. Particularly, soil water vapor adsorption has received little attention at field scale. This term is used for the phase change of water from gas to liquid at highly negative matric potential. Under such conditions, water condensates already at relative humidity < 100%. The process has been broadly studied in laboratories but little is known from field experiments, which rarely cover periods longer than one month. Yet, several studies report soil water uptake from the atmosphere during soil surface cooling and in the early mornings. Lysimeters have played a strong role in quantifying these NRWI. Eddy Covariance (EC) measurements, in contrast, are known for their limited data quality under nighttime conditions when a stable boundary layer hinders the turbulent exchange of mass and energy. Therefore, EC has not been tested yet to trace soil adsorption.<br>    <br>In this contribution we adapt a methodology to derive NRWI from lysimeters data and compare them to EC measurements. We focus mainly on adsorption and evaluate the consistency between adsorption estimated with the lysimeters and negative (downward) latent heat (LE) fluxes from EC. We apply the method to a data set that comprises three years of observations from a semi-arid Spanish tree grass ecosystem. </p><p>Our results show that during the dry season the gradient in water vapour established between the atmosphere (more humid) and the soil pores (more dry) leads to adsorption by the soil. The observations from both instruments suggest that during the dry season, nightly transport of humidity from the atmosphere towards the ground is driven by soil vapor adsorption. This process occurs each night typically in the second half, but begins increasingly earlier in the evening the dryer the conditions are. The amount of water adsorbed is not directly comparable between EC and the lysimeter readings. With the latter, we quantified a yearly mean uptake between 8.8 mm and 25 mm per year. With the lysimeters we measure additionally 23.1 mm of water that condenses as dew and fog in winter, when EC is impeded by stable conditions. We further analyze EC LE measurements from different sites to evaluate if adsorption can be detected from EC data collected at different locations.</p><p>We conclude that the temporal patterns of adsorption estimates from lysimeters match the nighttime negative LE data from the EC technique, although the absolute numbers are uncertain. This might open interesting perspective to fill the knowledge gap of the role of soil water vapor adsorption from the atmosphere at field scale and open the opportunity to broaden the topic across ecosystem research communities. Our results also highlight a potential shortcoming in the interpretation of EC measurements in the case that negative nighttime values, representing physically plausible adsorption, are neglected.</p>

Nigeria's Legal Instruments for Land and Water Use

2015 ◽  
pp. 354-373 ◽  
Author(s):  
David O. Omole ◽  
Julius M. Ndambuki
Keyword(s):  
Land Use ◽  
Water Resources ◽  
Water Use ◽  
Current System ◽  
Current Situation ◽  
Decision Makers ◽  
Main Thrust ◽  
The Government ◽  
Private Investors ◽  
Governing Institutions

This chapter critically assesses the administration of land and water resources in Nigeria. Reasons why the Land Use Act has not met its objectives are discussed. It also assesses reasons why, despite abundant water resources, numerous laws, and multiple governing institutions, Nigeria is still struggling to meet the national demand for water supply. The chapter concludes by suggesting specific amendments to the administration of both land and water resources. The main thrust of the suggested amendments is to address the current situation where government arrogates absolute authority on all land and water resources to itself. It is suggested that the government should consider adopting a multi-lateral relationship where government, private investors, traditional landowners, and prospective land buyers are co-decision makers in charting the future for the administration of land and water resources. This is aimed at eliminating associated problems such as delays, tenure insecurity, and proliferation of peri-urbanization in the current system.

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