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Water Balances and Multidimensional Models
Published in James L. Martin, Steven C. McCutcheon, Robert W. Schottman, Hydrodynamics and Transport for Water Quality Modeling, 2018
James L. Martin, Steven C. McCutcheon, Robert W. Schottman
The continuity equation or water balance is applied in lake and reservoir modeling for two purposes. First is to describe the water budget Second, the continuity equation is used to describe the change in storage and derive routing equations that are the basis of reservoir design for flood storage. Before conducting any water quality study, regardless of the dimensions of the model used, a correct water balance is required. The water balance is used to compare changes in storage with tributary and point source inflows and outflows of withdrawals to ensure that all sources and losses of water are known. Knowing changes in storage is necessary to simulate water quality variations. The solution to the continuity equation alone also forms the basis for the reservoir routing models, commonly used in reservoir design. Reservoir routing models, similar to the stream routing models described in Part II are often used to estimate the storage capacity required to hold a particular inflow.
Soil Water Balance Simulation of Rice using HYDRUS-2D and Mass Balance Model
Published in Balram Panigrahi, Megh R. Goyal, Modeling Methods and Practices in Soil and Water Engineering, 2017
Laxmi Narayan Sethi, Sudhindra Nath Panda
A fundamental part of understanding and improving water management is quantitative estimates of the major components of field water balance in the rainfed agriculture. However, the proper estimation of different water balance components in the root zone of the cropped field can help to achieve the effective use of the rainwater to increase the productivity. So, in the present study, field water balance and HYDRUS-2D models was used to quantify the water balance parameters such as runoff, actual evapotranspiration, vertical percolation and lateral seepage from the effective root zone of rice (450 mm) field with different weir heights (0, 50 and 100 mm). Three years (2002-04) field observations from experimental Farm of IIT, Kharagpur, India were used for testing of model predictions. HYDRUS-2D was used to simulate soil water content, lateral seepage and vertical percolation in the effective root zone of rice field with different weir heights under variable saturated condition. However, field water balance model was used to simulate water balance parameters such as actual evapotranspiration, runoff, lateral seepage and vertical percolation under both ponding (above saturation) and unsaturated condition. Higher overall prediction efficiency and coefficient determination (more than 0.75) as well as lower RMSE values reveals that, the HYDRUS-2D and field water balance model can be used for to simulate the different water balance parameters in effective crop root zone of rice with different weir heights.
Water Pollution and its Control
Published in Danny D. Reible, Fundamentals of Environmental Engineering, 2017
Analysis of a primary settler/clarifier requires an estimation of the residence time (or alternatively, cross-sectional area) of a clarifier section to ensure removal of a given particle size in the effluent water and an estimation of the removal rate of solids to avoid their accumulation in the settler/clarifier. A full thickener/clarifier is shown schematically in Figure 7.19. A water balance indicates that the total volume flow into the system is balanced by the effluent water (the overflow) and the underflow containing solids as well as residual water. With the overflow, there are essentially no residual solids (at least by design), while the underflow contains a high concentration of solids.
Vulnerability assessment of water resources using GIS, remote sensing and SWAT model – a case study: the upper part of Dong Nai river basin, Vietnam
Published in International Journal of River Basin Management, 2022
Pham Hung, Trung Van Le, Phu Le Vo, Hung Cong Duong, Md. Mostafizur Rahman
The water resource VI assessment is a complex process requiring a lot of information related to factors of the natural environment and socio-economic factors. The process involves enormous works such as assessing water balance; understanding the ecosystems, environment and economics; evaluating hydrological cycle and water quality; integrating data on geographic information systems (GIS) (Jolk et al., 2015) and examining social and economic aspects of water management on different scales. In particular, the water balance assessment is a complicated process related to the input and output of water (Nugroho et al., 2013). On the whole watershed, water balance refers to the balance between incoming water by precipitation, and outgoing water from evapotranspiration, groundwater recharge and streamflow (Suryatmojoa et al., 2013). Water balance is always disturbed by the instability of the climate conditions and changes in land use. Climate change has significantly affected the hydrological conditions, while the changes in land use and land cover (LULC) have continuously skewed the water balance. Somewhere, due to population growth, urbanization and socio-economic development, water use for agricultural, industrial and municipal interests uncontrollably rise, in some cases exceeding existing supplies, so that vulnerability of water resource also increases (Al-Kalbani et al., 2014).
Water balance analyzis using Palmer Drought Severeity Index for drought-prone region of Marathwada, India
Published in International Journal of River Basin Management, 2022
Richa Dhawale, Saikat Paul, Jeeno Soa George
Water balance studies are becoming vital due to the increasing demand for freshwater in the domestic, industrial, and agricultural sectors (Aquastat, 2011; Arjun, 2017). Water balance is considered one of the important components while planning irrigational schemes in drought-prone areas (Arjun, 2017). It requires knowledge of water availability for current and impending conditions for various sectors to balance the water resource (Sokolov & Chapman, 1974). It is calculated based on three components, which are potential evapotranspiration (PET), monthly rainfall, water surplus or deficit (moisture departure) (Arjun, 2017; Mintz & Serafini, 1992). The net change in the supply and demand of water define7s moisture departure (Mckee et al., 1993; Vasiliades & Dalezios, 2002). Supply is precipitation and stored soil moisture (Mckee et al., 1993), whereas demand is potential evapotranspiration (PET) and runoff. PET is the amount needed to recharge the soil, and runoff keeps the rivers, lakes, and reservoirs at a normal level.
Predicting soil water content using support vector machines improved by meta-heuristic algorithms and remotely sensed data
Published in Geomechanics and Geoengineering, 2021
Mir Naser Navidi, Javad Seyedmohammadi, Seyed Alireza Seyed Jalali
Soil and water are the most important resources that need to be carefully scrutinised for the sustainable management of agricultural systems. Soil hydraulic properties can be used to describe the interaction between soil and water. Hydraulic properties of soil including soil moisture content as a function of matrix suction is effective in soil and water solute transport, drainage, evapotranspiration, water uptake by plants, movement of water pollutants vadose zone, crop systems, tillage management and application irrigation planning in optimising the utilisation of resources in agricultural systems (Haghverdi et al. 2018). Soil water balance is essential for many processes that affect plant growth and degradation of soil and water resources. The amount of soil water available to the plant is the most important soil factor that controls crop yield. Predicting the amount of soil water and also making it available to meet the water needs of crops will allow farmers to make informed decisions and maximise profitability (Rab et al. 2011, Castellini and Iovino 2019). On the other hand, measuring and determining soil water by direct methods is often costly and time consuming and requires special equipment. Therefore, researchers are often looking for an alternative solution with acceptable accuracy that allows it to be estimated from easily measurable soil properties (Mosaddeghi and Mahboubi 2011, Botula et al. 2013).