scholarly journals Assessing Climate Change Impacts on Streamflow, Sediment and Nutrient Loadings of the Minija River (Lithuania): A Hillslope Watershed Discretization Application with High-Resolution Spatial Inputs

Water ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 676 ◽  
Author(s):  
Natalja Čerkasova ◽  
Georg Umgiesser ◽  
Ali Ertürk

In this paper we focus on the model setup scheme for medium-size watershed with high resolution, multi-site calibration, and present results on the possible changes of the Minija River in flow, sediment load, total nitrogen (TN), and total phosphorus (TP) load in the near-term (up to 2050) and long-term (up to 2099) in the light of climate change (RCP 4.5 and RCP 8.5 scenarios) under business-as-usual conditions. The SWAT model for the Minija River basin was setup by using the developed Matlab (SWAT-LAB) scripts for a highly customized watershed configuration that addresses the specific needs of the project objective. We performed the watershed delineation by combining sub-basin and hillslope discretization schemes. We defined the HRUs by aggregating the topographic, land use, soil, and administrative unit features of the area. A multisite manual calibration approach was adopted to calibrate and validate the model, achieving good to satisfactory results across different sub-basins of the area for flow, sediments and nutrient loads (TP and TN). After completing the climate change scenario calculations, we found that a net decrease of flow (up to 35%), TN (up to 34%), and TP (up to 50%) loads are projected under both scenarios. Furthermore, we explored the changes in the streamflow composition and provide new insight on the reason of projected nutrient load decrease.

2002 ◽  
Vol 6 (2) ◽  
pp. 197-209 ◽  
Author(s):  
F. Bouraoui ◽  
L. Galbiati ◽  
G. Bidoglio

Abstract. This study assessed the impact of potential climate change on the nutrient loads to surface and sub-surface waters from agricultural areas and was conducted using the Soil and Water Assessment Tool (SWAT) model. The study focused on a 3500 km2 catchment located in northern England, the Yorkshire Ouse. The SWAT model was calibrated and validated using sets of five years' measurements of nitrate and ortho-phosphorus concentrations and water flow. To increase the reliability of the hydrological model predictions, an uncertainty analysis was conducted by perturbing input parameters using a Monte-Carlo technique. The SWAT model was then run using a baseline scenario corresponding to an actual measured time series of daily temperature and precipitation, and six climate change scenarios. Because of the increase in temperature, all climate scenarios introduced an increase of actual evapotranspiration. Faster crop growth and an increased nutrient uptake resulted, as did an increase of annual losses of total nitrogen and phosphorus, however, with strong seasonal differences. Keywords: SWAT model, climate change, nutrient loads


Hydrology ◽  
2021 ◽  
Vol 8 (4) ◽  
pp. 157
Author(s):  
Giuseppe Pulighe ◽  
Flavio Lupia ◽  
Huajin Chen ◽  
Hailong Yin

The consequences of climate change on food security in arid and semi-arid regions can be serious. Understanding climate change impacts on water balance is critical to assess future crop performance and develop sustainable adaptation strategies. This paper presents a climate change impact study on the water balance components of an agricultural watershed in the Mediterranean region. The restructured version of the Soil and Water Assessment Tool (SWAT+) model was used to simulate the hydrological components in the Sulcis watershed (Sardinia, Italy) for the baseline period and compared to future climate projections at the end of the 21st century. The model was forced using data from two Regional Climate Models under the representative concentration pathways RCP4.5 and RCP8.5 scenarios developed at a high resolution over the European domain. River discharge data were used to calibrate and validate the SWAT+ model for the baseline period, while the future hydrological response was evaluated for the mid-century (2006–2050) and late-century (2051–2098). The model simulations indicated a future increase in temperature, decrease in precipitation, and consequently increase in potential evapotranspiration in both RCP scenarios. Results show that these changes will significantly decrease water yield, surface runoff, groundwater recharge, and baseflow. These results highlight how hydrological components alteration by climate change can benefit from modelling high-resolution future scenarios that are useful for planning mitigation measures in agricultural semi-arid Mediterranean regions.


Agriculture ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 605
Author(s):  
Alba Piña-Rey ◽  
Estefanía González-Fernández ◽  
María Fernández-González ◽  
Mª. Nieves Lorenzo ◽  
Fco. Javier Rodríguez-Rajo

Viticultural climatic indices were assessed for the evaluation of the meteorological variations in the requirements of wine cultivars. The applied bioclimatic indices have been widely used to provide an initial evaluation of climate change impacts on grapevine and to delineate wine regions and suitable areas for planting around the world. The study was carried out over a period of 16 years (from 2000 to 2015) in five Designation of Origin areas in Northwestern Spain located in the Eurosiberian region, the transition zone between the Eurosiberian and the Mediterranean areas, and in the Mediterranean area. In addition, the high-resolution meteorological dataset “Spain02” was applied to the bioclimatic indices for the period 1950–2095. To further assess the performance of “Spain02”, Taylor diagrams were elaborated for the different bioclimatic indices. A significant trend to an increase of the Winkler, Huglin, Night Cold Index and GSS Indices was detected in the North-western Spain, whereas slight negative trends for BBLI and GSP Indices were observed. To analyze future projections 2061–2095, data from the high-resolution dynamically downscaled daily climate simulations from EURO-CORDEX project were used. To further assess the performance of Spain02, Taylor diagrams were elaborated for the different bioclimatic indices. A trend to an increase of the Winkler, Huglin, Night Cold Index and GSP Indices was detected in Northwestern Spain, whereas slight negative trends for BBLI and GSP Indices were observed. Our results showed that climatic conditions in the study region could variate for the crop in the future, more for Mediterranean than Eurosiberian bioclimatic area. Due to an advance in the phenological events or the vintage data, more alcohol-fortified wines and variations in the acidity level of wines could be expected in Northwestern Spain, these processes being most noticeable in the Mediterranean area. The projections for the BBLI and GSP Indices will induce a decrease in the pressure of the mildew attacks incidence in the areas located at the Eurosiberian region and the nearest transition zones. Projections showed if the trend of temperature increase continues, some cultural practice variations should be conducted in order to preserve the grape cultivation suitability in the studied area.


Water ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1556 ◽  
Author(s):  
Daeeop Lee ◽  
Giha Lee ◽  
Seongwon Kim ◽  
Sungho Jung

In establishing adequate climate change policies regarding water resource development and management, the most essential step is performing a rainfall-runoff analysis. To this end, although several physical models have been developed and tested in many studies, they require a complex grid-based parameterization that uses climate, topography, land-use, and geology data to simulate spatiotemporal runoff. Furthermore, physical rainfall-runoff models also suffer from uncertainty originating from insufficient data quality and quantity, unreliable parameters, and imperfect model structures. As an alternative, this study proposes a rainfall-runoff analysis system for the Kratie station on the Mekong River mainstream using the long short-term memory (LSTM) model, a data-based black-box method. Future runoff variations were simulated by applying a climate change scenario. To assess the applicability of the LSTM model, its result was compared with a runoff analysis using the Soil and Water Assessment Tool (SWAT) model. The following steps (dataset periods in parentheses) were carried out within the SWAT approach: parameter correction (2000–2005), verification (2006–2007), and prediction (2008–2100), while the LSTM model went through the process of training (1980–2005), verification (2006–2007), and prediction (2008–2100). Globally available data were fed into the algorithms, with the exception of the observed discharge and temperature data, which could not be acquired. The bias-corrected Representative Concentration Pathways (RCPs) 4.5 and 8.5 climate change scenarios were used to predict future runoff. When the reproducibility at the Kratie station for the verification period of the two models (2006–2007) was evaluated, the SWAT model showed a Nash–Sutcliffe efficiency (NSE) value of 0.84, while the LSTM model showed a higher accuracy, NSE = 0.99. The trend analysis result of the runoff prediction for the Kratie station over the 2008–2100 period did not show a statistically significant trend for neither scenario nor model. However, both models found that the annual mean flow rate in the RCP 8.5 scenario showed greater variability than in the RCP 4.5 scenario. These findings confirm that the LSTM runoff prediction presents a higher reproducibility than that of the SWAT model in simulating runoff variation according to time-series changes. Therefore, the LSTM model, which derives relatively accurate results with a small amount of data, is an effective approach to large-scale hydrologic modeling when only runoff time-series are available.


2015 ◽  
Vol 16 (2) ◽  
pp. 762-780 ◽  
Author(s):  
Pablo A. Mendoza ◽  
Martyn P. Clark ◽  
Naoki Mizukami ◽  
Andrew J. Newman ◽  
Michael Barlage ◽  
...  

Abstract The assessment of climate change impacts on water resources involves several methodological decisions, including choices of global climate models (GCMs), emission scenarios, downscaling techniques, and hydrologic modeling approaches. Among these, hydrologic model structure selection and parameter calibration are particularly relevant and usually have a strong subjective component. The goal of this research is to improve understanding of the role of these decisions on the assessment of the effects of climate change on hydrologic processes. The study is conducted in three basins located in the Colorado headwaters region, using four different hydrologic model structures [PRMS, VIC, Noah LSM, and Noah LSM with multiparameterization options (Noah-MP)]. To better understand the role of parameter estimation, model performance and projected hydrologic changes (i.e., changes in the hydrology obtained from hydrologic models due to climate change) are compared before and after calibration with the University of Arizona shuffled complex evolution (SCE-UA) algorithm. Hydrologic changes are examined via a climate change scenario where the Community Climate System Model (CCSM) change signal is used to perturb the boundary conditions of the Weather Research and Forecasting (WRF) Model configured at 4-km resolution. Substantial intermodel differences (i.e., discrepancies between hydrologic models) in the portrayal of climate change impacts on water resources are demonstrated. Specifically, intermodel differences are larger than the mean signal from the CCSM–WRF climate scenario examined, even after the calibration process. Importantly, traditional single-objective calibration techniques aimed to reduce errors in runoff simulations do not necessarily improve intermodel agreement (i.e., same outputs from different hydrologic models) in projected changes of some hydrological processes such as evapotranspiration or snowpack.


2020 ◽  
pp. 22-31 ◽  
Author(s):  
Nguyen Kim Loi ◽  
Vo Ngoc Quynh Tram ◽  
Nguyen Thi Tinh Au

Climate is the main factor affecting hydrology in a watershed. For purely agricultural watershed, hydrological assessment and management play a very important role in the region's agricultural development. In this study, the hydrological was simulated by the Soil and Water Assessment Tool (SWAT) model. This paper aimed to calibrate and validate the SWAT model in Dak B’la watershed in Central Highland Vietnam and assess the climate change on water discharge. The coefficient of determination (R²) and Nash-Sutcliffe index (NSI), and Percent BIAS (PBIAS) during the calibration process was 0.75, 0.72, and -1.15 respectively and validation process was 0.82, 0.83, 3.67 respectively. It proved the high reliability of the SWAT model after calibration. The two climate scenarios were selected in this investigation: scenario A is the existing climate using the data from 2001 to 2018 and scenario B is the A1B emission scenario for the future period from 2020 to 2069. Compared to the average water discharge from 2001-2018 and average water discharge from 2020 to 2069, the results indicated that climate change increases the average water discharge (0.55%), especially in 2050, the water discharge in the flood season (in November) is 584 m3/s, which higher than the largest flood in 2009 of 450 m3/s.


2020 ◽  
Author(s):  
Sylvia Tramberend ◽  
Günther Fischer ◽  
Harrij van Velthuizen

<p>Climate change threatens vulnerable communities in sub-Saharan Africa who face significant challenges for adaptation. Agriculture provides the livelihood for the majority of population. High-resolution assessments of the effects of climate change on crop production are urgently needed for targeted adaptation planning. In Ghana, next to food needs, agriculture plays an important role on international cocoa markets. To this end, we develop and apply a National Agro-Ecological Zoning system (NAEZ Ghana) to analyze the impacts of high-end (RCP8.5) global warming on agricultural production potentials until the end of this century. NAEZ Ghana uses an ensemble of the CORDEX Africa Regional Climate Model, a regional soil map, to assess development trends of crop production potentials for 19 main crops. Results highlight differential impacts across the country. Especially due to the significant increase in the number of days exceeding high-temperature thresholds, rain-fed production of several food and export crops could be reduced significantly compared to the historical 30-year average (1981-2010). Plantain production, an important food crop, could achieve under climate change less than half of its current potential already in the 2050s and less than 10% by the 2080s. Suitable areas for cocoa production decrease strongly resulting in only one third of production potential compared to today. Other crops with detrimental effects of climate change include oil palm, sugarcane, coffee, and rubber. Production of maize, sorghum, and millet cope well with a future warmer climate. The NAEZ Ghana database provides valuable high-resolution information to support agricultural sector development planning and climate change adaptation strategies. The expansion of irrigation development will play a central role in some areas. This requires further research on Ghana’s linkages between food, water, and energy, taking into account climate and socio-economic changes.</p>


2021 ◽  
Author(s):  
Patrick Keys ◽  
Matthew Keys

Story-based futures serve an important role in climate change scenario development. Stories are particularly useful in exploring sea level rise possibilities, since we know many coastal areas are specifically vulnerable to accelerating rises in sea level. This discrete change in coastline is different from most other climate change impacts, and offers a clear basis for scientifically-informed, future scenarios. We demonstrate this with a creative world-building effort set in Lagos, Nigeria, in the year 2199. Further, we employ story-based scenario development, and create a learning-oriented, web-based game that allows users to experience stories in an open-ended, text-based adventure style. This collaborative process blended scientific research, story-telling, and artistic co-creation to iteratively construct the game ‘Lagos2199’. The first use-case of Lagos2199 is documented herein, with corresponding survey results from the student users. This work has three core conclusions. First, the unique reality that sea level rise will literally re-draw maps can be leveraged as an entry-point for world-building and scenario development of the future. Second, such a scenario can be blended with storytelling, art, and music to create a multi-dimensional, immersive exploration of ecological and social change. Third, this kind of game experience can serve an important pedagogical role in climate change education. Providing the next generation of citizens with fluency in both climate change impacts and how society will interact with such impacts, is critical for providing adaptive capacity over the coming decades and centuries of accelerating global change.


2017 ◽  
Author(s):  
Sangchul Lee ◽  
In-Young Yeo ◽  
Ali M. Sadeghi ◽  
Gregory W. McCarty ◽  
Wells D. Hively ◽  
...  

Abstract. Water quality problems in the Chesapeake Bay Watershed (CBW) are expected to exacerbate under climate variability and change. However, climate impacts on agricultural lands and resultant nutrient loads into surface water resources are largely unknown. This study evaluates the impacts of climate variability and change on two adjacent watersheds in the Coastal Plain of the CBW, using Soil and Water Assessment Tool (SWAT) model. We prepared six climate sensitive scenarios to assess the individual effects of variations in CO2 concentration (590 and 850 ppm), precipitation increase (11 and 21 %) and temperature increase (2.9 and 5.0 °C), and considered the predicted climate change scenario using five general circulation models (GCMs) under the Special Report on Emissions Scenarios (SRES) A2 scenario. Using SWAT model simulations from 2001 to 2014, as a baseline scenario, the predicted water and nitrate budgets under climate variability and change scenarios were analyzed at multiple temporal scales. Compared to the baseline scenario, precipitation increase of 21 % and elevated CO2 concentration of 850 ppm significantly increased stream flow and nitrate loads by 50 % and 52 %, respectively, while, temperature increase of 5.0 °C reduced stream flow and nitrate loads by 12 % and 13 %, respectively. Under the climate change scenario, annual stream flow and nitrate loads showed an average increase of nearly 40 %, relative to the baseline scenario. Differences in hydrological responses observed from the two watersheds were primarily attributed to contrasting land use and soil characteristics. The watershed with larger percent croplands indicated increased nitrate yield of 0.52 kg N ha−1 compared to the one with less percent croplands under the climate change scenario, due to increased export of nitrate derived from fertilizer. The watershed dominated by poorly-drained soils showed a lower increase in nitrate yield than one dominated by well-drained soils, due to a high potential of nitrate loss in surface runoff and enhanced denitrification. To mitigate increased nitrate loads potentially caused by climate change, the enhanced implementation of conservation practices would be necessary for this region in the future. These findings assist watershed managers and regulators as they seek to establish effective adaptation strategies to mitigate water quality degradation in this region.


2019 ◽  
Vol 50 (2) ◽  
pp. 88-98
Author(s):  
Lanie A. Alejo ◽  
Victor B. Ella

Seasonal changes in rainfall and temperature brought about by climate change affect water resources availability for rice production areas. There are currently no published applications of the soil and water assessment tool (SWAT) model on quantified effects of climate variability on irrigation service areas for rice production. The study assessed the impacts of climate change on dependable flow and potential irrigable areas of the Maasin River in Laguna, Philippines. Projected variations of rainfall and temperature in 2020 and 2050 developed using PRECIS model based on special report on emission scenarios were employed. The SWAT model was then used to simulate stream flow for each climate change scenario, from which dependable flows were quantified using flow duration analysis. Diversion water requirements for the rice areas in the watershed were determined using CROPWAT. Based on dependable flows and irrigation demand, the potential irrigable areas were estimated. Calibration and validation of the SWAT model showed satisfactory performance in stream flow simulations. The dependable flow in irrigation systems may decline by more than 50% in 2020 and by as much as 97% in 2050, because of seasonal changes in rainfall. In effect, the potential irrigable area may decrease to less than half of the current service area depending on the level of greenhouse gases emissions. SWAT water balance projections suggest surface runoff during wet seasons and increase annual groundwater recharge are possible sources of supplemental irrigation. Provisions of suitable storage reservoir facilities and groundwater development projects will alleviate water scarce conditions. The study demonstrated a technique that may be applied in other irrigation systems in the Philippines and in other countries to quantify the effects of climate change on dependable flows and potential irrigable areas. It can serve as an input to water resources planning and policy recommendations for climate change adaptation and risk reduction strategies. This technique can also be used to assess water resources in other perennial rivers and its viability for the development of new irrigation systems in the Philippines.


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