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2.5.1 Surface Water Storage
Surface water storage are surface detention plus depression storage. Surface detention is a portion of rainwater which remains in temporary storage on the land
surface as it moves downslope by overland flow and either runs off, evaporated or infiltrated after the rain ends. Surface detension is the storage effect due to the
overland flow in transit Chow, 1988. Depression storage is the volume of water, forming part of surface detention, which is contained in small natural depressions in
the land surface during or shortly after rain fall, none of which run off Tischendorf, 1969.
2.5.2 Soil Water Storage
A part of raindrop falls, penetrates the land surface, or infiltrates into the ground. The amount of infiltration, or infiltration rate, is variable among different soil
even for a given soil it is variable and dependent on the previous dampness, or antecendent moisture, condition of the soil. Infiltrated water may become part of the
soil‘s field moisture Chorley, 1978. Soil moisture is all water which is stored in the weathered soil mantle Tischendorf, 1969. Soil moisture storage is the quantity of
water that can be permanently retain in the soil in opposition to the down ward pull of gravity Horton, 1933.
2.6 Land Use Suitability
Land evaluation is a process for syncronize the characteristics of land resources for certain uses using a scietifically standardized technique. The result can
be used as a guide by land users and planners to identify alternative land uses. Land Suitability is the degree of appropriateness of land for a certain use.
Landsuitability could be assessed for present condition Actual Land Suitability or after improvement Potential Land Suitability.
Actual Land suitability is a land suitability that based on current soil and land conditions, i.e. without applying any input. The information is based on physical
environment data generated from soil or land resource surveys. The information is based on soil characteristic and climate data related to growth requirement of crops
being evaluated. Potential Land Suitability is the suitability that could be reached after the land is improved.
The land to be evaluated can be natural conversion forest, abandoned or unproductive lands, or land that currently used for agriculture, at a sub-optimal level
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of management in such a way that the productivity can be improved by changing to more suitable crops Ritung et al, 2007.
Incorrect land use plan would bring natural degradation and soil erosion. It changes the balance of the hydrological cycle. Incorrect land use plan are also water
pollution, habitat destruction, energy use increase, air pollution, and quality of life reduction Randolph, 2004. The purpose of land use plan is to create harmonious
relations between various activities in the territory in order to create its harmonious relation. It will accelerate the process of achieving prosperity and ensuring
environmental sustainability Tarigan, 2004. Environmental sustainability is sustainable environmental protection for next generations. The main goals are both
renewable and sustainable water Albertson, 1999.
2.7 Water Availability
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