WaBcal-A Calculator for Preparing Water Budget of Discrete Land Unit

WaBcal is a calculator to prepare water budget of any discrete land unit. It is developed in C language and follows water budget norms proposed by National Agriculture Commission (1972,2002). Major input to the model is normal rainfall of that area and this is proportionately equated into surface flow, ground water flow, evaporation at various stages and magnitude, soil moisture etc. The calculator considers different water needs of the area which include demand from agriculture, domestic, livestock and industries. Total 27 field crop, nine vegetables and six fruit crop and six other crops are prevailing in Madhya Pradesh that may be used for computing agriculture demand. 18 Animals are considered for live stalk demand. Population gives domestic water demand. As an output the calculator gives water surplus/deficit of the study area.

Water budget of an area helps in understanding water potential and its current use/loss. Once the available quantum is known its optimal allocation for different purposes can maximize gain from that area. Healy et al. (2007) illustrate importance of having water budget of any basin in hand for planning agricultural, cultural, environmental and social planning. (Kumar 2012) pointed out that water balance techniques have been extensively used to make quantitative estimates of water resources. The GW availability of an area can also be assessed with water fluctuation method. Khare et al. (2006) assessed surface and ground water resources availability for irrigation in Sapon irrigation command. Indonesia. Water resource assessment at basin level using water balance approach and remote sensing has also in practice with proper hydrological model selection and its parameterization (Shriadhionkar 2015). Water balance may also be used for estimation of Evapotranspiration (Jain 2012), ground water potential of basin (Maurya, 2017) and evaluation of different catchment modules Dhage et al. (2014). A study of demand and supply of water in India was analyzed by (Bhatt 2014). He postulated reasons for increasing demand of water as population growth, growing urbanization and agriculture etc.
A programme, WaBcal (~webkel), has been developed and presented in this paper written in C, for calculating water available for utilization and also for computing water needs from different sectors.

MATERIALS AND METHODS
National Commission on Agriculture (NCA, 1972(NCA, , 2002 has suggested different components of water budget and their partial magnitude. Like other water budgeting it also has major/sole input of rainfall when falls over an area, which is much as a discrete unit, generates total volume of available water. Its distribution, as per NCA, into Immediate evaporation (17.5%), Surface flow (28.7%), From outside state(10.549% of total surface flow), To GW from flood flows (-4.851% of total surface flow), From GW to surface flow (23.739% of total surface flow), From irrigated area to surface flow (7.067% of total surface flow), Total surface flow(45.198% of total ppt), Evaporation lossess from reservoirs and tanks (7.916% of total surface flow), Flow into seas and outside state (43.445% of total surface flow), Utilizable surface flow (48.639% of total surface flow), Water available for ground water storage (12.5%), From streams and flood flows to GW (4.851% of total surface flow), From irrigation to GW addition (S.N.14-(11+12)), Total GW (21.492% of total ppt), Evaporation and rise of water table (18.451% of total GW), Regeneration into streams (49.924% of total GW), GW available utilization (31.625% of total GW), Total utilizable surface + GW (S.N. 10+17), Soil moisture storage (41.3% of normal rainfall), From irrigated area to soil moisture (7.067% of total surface flow), Total soil moisture storage (44.495% of total ppt), Evaporation lossess from soil moisture (31.504% of total soil moisture storage), Evap. lossess from forest and other veg. (30.826% of total soil moisture), Soil moisture available for ET from crops (37.673% of total soil moisture)and Water available for utilization (S.N. 18+24).
The demand arises from agriculture sector, domestic needs, livestalk and from industries. The total demand when subtracted from the water available for utilization results into water surplus/deficit situation. Awasthi et al. (2017) prepared water budget of all districts of Madhya Pradesh and have been a basis of verifying results obtained from WaBcal.
Water needs from different crops may be computed through following procedure.  Total water needs of all live stalk is computed as = ∑ L i N i Where, L i and N i are respectively water need and numbers of i th animal (iv) Industrial need -Irrespective of the intensity of industrialization, the allocation towards this sector may be taken as six percent of available fresh water.
The flow diagram representing the process for water budgeting is given in Fig. 1.

Programme development
The program WaBcal is designed in 'c' programming language that needs following INPUTS to assess the water budget of any discrete land unit selected for study.