Potential Water Balance Research Articles

ANALISIS NERACA AIR PERTANIAN DI SUB DAS RAWATAMTU (Analysis of agricultural water balance in Rawatamtu sub-watershed)

Population growth, urbanization, industrial development, and agricultural activities increase water demand on the watershed. An increase in water demand will propagate the excessive exploitation of surface water and groundwater resources. This will probably influence the water balance of the watershed. Therefore, understanding the water balance is a necessity. Continuous imbalance between water supply and demand will generate many serious environmental problems. A study of agricultural water balance is needed to answer the question whether the available water resources can meet the needs of sufficient water for irrigation. The study was conducted in Rawatamtu sub-watershed which was part of Bedadung Watershed. The Water Evaluation and Planning (WEAP) model was used to analyze agricultural water balance. The procedure included inventory data, installing WEAP on the system, running the WEAP, and using WEAP for simulating future water balance conditions. The simulation results showed that agricultural water balance for the next 10 years will be more frequently in surplus condition rather than in deficit condition. The water surplus was estimated to occur in the year of 2020, 2021, 2023, 2025, 2027 and 2028. The highest surplus occurred in the year of 2028 which reached 56.59 million m3. Furthermore, the potential water balance deficit was projected to occur in 2019, 2022, 2024 and 2026.

Estimation of Evapotranspiration for Onion Crop in Semi-Arid Region: Experimental Field Setup Using Lysimeter

In this work, Blaney-Criddle and Lysimeter method were applied to evaluate the actual evapotranspiration for onion crop in the semi-arid region of Chitradurga district. A reliable and accurate estimation of evapotranspiration are required for proper water balance and to define water-crop requirement. For this purpose, Lysimeter was set up in the field using three different soil layers of specific gravity 2.30. In this research work, an attempt is made to estimate daily evapotranspiration for onion crop, for which 1000ml of water was added on daily basis and corresponding percolation was observed to find the potential water balance deficit and surplus. Onion is a local crop of Chitradurga district having growth rate 90-120 days. For Blaney-Criddle equation, crop coefficient of 0.75 is adopted to estimate the actual evapotranspiration. This method was found to be simple and reliable to estimate the evapotranspiration in semi-arid region.

Impact of statistical bias correction on the projected climate change signals of the regional climate model REMO over the Senegal River Basin

We assess the impact of a statistical bias correction method based on histogram equalization functions on the projected climate change signals of regional climate model (RCM) simulations over the Senegal River Basin in West Africa. Focus is given to projected changes in precipitation, temperature, and potential water balance (P − PET) following the RCP4.5 and RCP8.5 emission scenario pathways by the end of the 21st century (2071–2100) compared to the 1971–2000 reference period. We found that applying the bias correction substantially improved the simulations of present day climate for both temporal and spatial variations of the analysed climate parameters when compared to gridded observations data sets and station data. For the future, the non-corrected RCM projections show a general decrease of precipitation by the end of 21st century for both scenarios over the majority of the basin, except the Guinean highlands where a slight increase is found. The reduction in mean precipitation is accompanied by a projected increase in the annual number of dry days, most pronounced in the northern basin. Furthermore, a general temperature increase is projected over the entire basin for both scenarios, but more pronounced under the RCP8.5 scenario. In addition, the deficit in the water balance (P − PET) above 12°N is projected to increase in the future. Applying the bias correction to the RCM projections leads to a general dampening of the projected change signals, strongest in the case of heavy precipitation events. However, for all analysed parameters the general directions of change as well as the predominant large-scale change patterns are conserved after applying the bias correction.

How do rubber (Hevea brasiliensis) plantations behave under seasonal water stress in northeastern Thailand and central Cambodia?

Delineating the characteristics of biosphere-atmosphere exchange in rubber (Hevea brasiliensis Müll. Arg.) plantations, which are rapidly expanding throughout mainland Southeast Asia, is important to understanding the impacts of the land-use change on environmental processes. In attempt to shed new light on the impacts of conversion to rubber, we have conducted eddy flux measurements over a 3-year period in two rubber plantation sites: (1) Som Sanuk, located in northeastern Thailand; and (2) Cambodian Rubber Research Institute (CRRI), located in central Cambodia. Both sites have a distinct dry season. We used a combination of actual evapotranspiration (ET) flux measurements and an inverted version of a simple 2-layer ET model for estimating the mean canopy stomatal conductance (gs). The potential water balance (precipitation (P)−potential evaporation (ET_POT)) for each season (i.e., December–February: DJF, March–May: MAM, June–August: JJA, and September–November: SON) revealed when and how the water use is controlled. In the seasons when actual water balance (P−ET) was negative (DJF and MAM), the deficit was compensated with soil water from the previous season at depths of 0–2m (Thailand site) and 0–3m (Cambodia site). At both sites, the reference value of gs (gsref) and the sensitivity of gs to atmospheric demand (m) appeared to be less in DJF and MAM than each in the other two 3-month periods (seasons). On average, in a whole year, m/gsref was less in Thailand (<<0.6) than in Cambodia (near 0.6 for part of the year), suggesting that there was less sufficient stomatal regulation at the Thailand site, where there might be little risk of water stress-induced hydraulic failure because of its higher annual rainfall amount. In comparison, at CRRI where annual P−ET_POT was negative, there was stricter stomatal regulation, preventing excessive xylem cavitation.

Application of climatic indices to analyse viticultural suitability in Extremadura, south-western Spain

Although climate is recognised as one of the main drivers of viticulture success, its main features have not been sufficiently described in many viticultural regions, including Extremadura, which contains one of the largest grapevine-growing areas in Europe. Using climatic data from 80 weather stations located throughout Extremadura, seven bioclimatic indices were calculated to estimate heat accumulation and potential water balance during the growing season and the thermal regime during the ripening of grapes. Differences in some climatic indices were found, and after a multivariate geographic analysis, four groups were delimited containing weather stations with similar climatic features, with variability between groups explained by heat accumulation and tempearture and thermal amplitude during the ripening season. Suitability for cultivation of grapevines without thermal restriction and temperate nights during the ripening period are the main characteristics of the weather stations studied, but spatial variability found in climatic potential denotes the importance of differentiating locations to properly relate the viticultural climate to grape quality factors and the style of wines produced. The climatic features of the four groups are very similar to those described in other viticultural regions, including those in close proximity to Extremadura and others worldwide, but few studies have used broad and updated temporal climate data for computing bioclimatic indices as in this case study. Finally, trends in climate indices were analysed. Results revealed that all groups have experienced warmer growing seasons, driven mainly by changes in minimum temperatures. This fact has numerous potential impacts, including changes in grapevine phenological timing, disruption of balanced composition in grapes (ultimately affecting wine characteristics), alterations in varieties grown and spatial changes in viable winegrape-growing zones.

Climatic potential for viticulture in Central Chile

Background and Aims: Central Chile represents a large area of viticultural potential for high‐quality wine production. Although climate has been commonly accepted as one of the main drivers of Chilean viticultural success, its main features have not been described from a viticultural perspective. Our work focused on analysing the spatial climatic structure in this area with respect to the potential for grapevine production. Methods and Results: Climatic indices were used to estimate heat accumulation during the growing season, thermal regime during ripening and the potential water balance at the end of the growth cycle. These indices were calculated for 54 weather stations and clustered using hierarchical classification. The spatial variability in climatic potential was well explained by differences in heat accumulation and by March thermal amplitude. Conclusions: General patterns showed that the ripening of grapes was associated with low night‐time temperatures. Proximity to the sea had a strong influence, and there was a dominant north–south orientation of the climatic groups. Significance of the Study: This study described the differences and relative importance of major climatic factors in Central Chile, providing an increase in knowledge about the climate of Chilean wine‐producing regions.

Evaluation of Climate Input Biases and Water Balance Issues Using a Coupled Surface–Subsurface Model

A physically based, coupled and distributed hydrologic model has been set up for the Ringkøbing Fjord catchment, Denmark. This transient model, built with the MIKE SHE/MIKE 11 code, comprises all major components of the terrestrial water cycle, including a three‐dimensional finite‐difference groundwater model. The dynamic coupling of the hydrologic processes secures physically sound feedback and makes the model an ideal tool for evaluating the overall water balance and quantifying potential water balance issues. Historically, failure to obtain water balance closure has been a persistent and much debated problem in Denmark, presumably arising mainly from uncertainties in precipitation, actual evapotranspiration, and groundwater flow to the sea. In this study, the water balance issues were addressed within the modeling framework through analysis of different rain gauge catch corrections and potential evapotranspiration input. The analysis focused on the effect of different rain gauge catch corrections on the model performance, the optimized parameter sets, and state variables not included in the model calibration. The results suggest that water balance problems can be reduced by using a dynamic rain gauge catch correction based on daily wind speed and temperature fields. The model optimization and performance evaluation revealed, however, that several parameter sets gave similar performance compared with the observed groundwater head and river discharge data but still resulted in significant differences with respect to internal water fluxes such as evapotranspiration, groundwater recharge, and stream flow components. New observational data are needed to constrain the model further and thus reduce the water balance uncertainties convincingly.

Sustainability of water resources development in the Komadugu Yobe River basin of Nigeria

A water audit of the Hadejia river sub-catchment of Komadugu Yobe River basin of Nigeria (KYB) has been carried out in order to elucidate the sustainability of existing water uses. Results show that about 2,619 million cubic meters (MCM) of surface water is available annually upstream of Wudil (HS 1), 658 MCM is available between Wudil and Hadejia (HS 2), while 905 MCM is available between Hadejia and Gashua (HS 3). Analysis of direct ground water recharge revealed that 86 mm, 94 mm and 8 mm of water is recharged to groundwater annually in the three hydrological sections HS 1, HS 2 and HS 3 respectively. It is obvious that the least ground water recharge takes place in the Hadejia - Nguru Wetlands. Presently, no water stress was observed in the sub-catchment; however, a number of water management problems persist all over the sub-catchment. The potential water balance of the area shows that about 75% of the available water between Wudil and Hadejia section (HS 2) would be used up by 2010 going by the current development rate. Projections show that the water use rate will reach 100% by 2018. At this time, water scarcity will commence in this area if urgent steps are not taken to address the situation. Adoptable strategies to avert the crisis were advanced. Keywords: Water, Development, Management, recharge, Nigeria Journal of Applied Science, Engineering and Technology , Volume9,: 5-17

A multicriteria climatic classification system for grape-growing regions worldwide

This study concerns firstly the methodology to describe the climate of vineyards, on a macroclimate scale of viticultural regions worldwide. Three synthetic and complementary viticultural climatic indices (potential water balance of the soil over the growing cycle, heliothermal conditions over the growing cycle and night temperature during maturation), validated as descriptors, are used: (1) dryness index (DI) which corresponds to the potential water balance of the soil of Riou’s index, here adapted using precise conditions to calculate it, as an indicator of the level of presence-absence of dryness; (2) heliothermal index (HI) which corresponds to Huglin’s heliothermal index; (3) cool night index (CI) an index developed as an indicator of night temperature conditions during maturation. These indices are representative of the variability of the viticultural climate worldwide, related to the requirements of varieties, vintage quality (sugar, colour, aroma), and typeness of the wines. A Multicriteria Climatic Classification System ( Géoviticulture MCC System) for the grape-growing regions worldwide is formulated based on classes for each of the three climate indices, with elements to explain the results. Three formulated concepts provide the system base: viticultural climate, climatic group and viticultural climate with intra-annual variability (for warm regions with more than one harvest a year in natural climate conditions). The application of the Géoviticulture Multicriteria Climatic Classification System is presented for 97 grape-growing regions in 29 countries. The system is a research tool for grape-growing and wine-making zoning. It also enables work at different levels on the scale, on a world-wide scale or larger – the large grape-growing region, the small grape-growing region, as shown by the studies performed. It allows relating the viticultural climate to the elements of grape quality and the typeness of the wines considering the climatic zone.

Potential water balance response to climatic warming: The case of a coastal wetland ecosystem of the James Bay Lowland

The present study investigates the potential impacts of climate warming on the water balance and vegetation patterns in a coastal wetland ecosystem on James Bay, Canada. The study illustrates some of the linkages within this system and how they might respond to a change in mean summer temperature. These linkages are outlined in a simple conceptual model with hydrology, salinity, topography, and vegetation distribution components. The model includes two feedbacks: a vegetation/evaporation feedback, and a hydrologic, runoff/storage feedback. A mathematical model is developed to examine changes in evaporation and water balance under a range of temperature change scenarios. Although the model is relatively insensitive to the internal feedbacks, model runs for temperature-change scenarios of +2 to +8°C above present summertime normal showed evaporation increased by 18 to 64%, respectively, which resulted in decreases, in wetland water table of 40 to 129% below the normal summer drawdown. These changes in basin storage significantly affect the distribution of woody species in the wetland. The basin area inhabited by woody species increased from the present 25% to 32% for a +2°C temperature change and to 51% for a +8°C change. Increased stomatal resistance of the wetland vegetation, which might result from increased CO2 concentrations, partially offsets the evaporation enhancement from warmer summer temperatures.

Global solar radiation and potential evapotranspiration in Sweden

By means of an established regression between monthly global solar radiation and monthly number of sunshine hours for eight stations in Sweden the global solar radiation has been calculated from values of sunshine hours for 35 Swedish stations for the period 1931-60. The distribution of global solar radiation in Sweden then has been mapped for the months April-September and the year. Potential evapotranspiration from a grass-covered surface has been calculated for 27 stations in Sweden for 1931-60 making use of the Penman formula and applying the values obtained for the global solar radiation. The distribution of total potential evapotranspiration has been mapped for April-September and the year. Comparisons are made with values earlier obtained in Sweden for actual evapotranspiration and diagrams showing the annual development of the potential water balance conditions are given for some typical Swedish stations. DOI: 10.1111/j.2153-3490.1966.tb00299.x