InsightsUnveiled

Water table is the upper level of the zone of saturation (ground water) in permeable rocks.It represents the surface at which the pressure in the ground water is equal to the atmosphereis pressure.It is situated below the zone of intermittent saturation.Level of sturation instead of water table is an appropiate term because the term water table indicates a horizontal surface which in fact rarely exists. Runoff is used to indicate pecipitation excess & is determined by deducting the loss from rainfall. The water table tends to sink as irt approaches a valley as runoff water readily escapes at the surface on the hillsides above the valley & drains off more rapidly.Interflow through beds of saturated permeable rocks occurs where ground water table is lower.   In Britain water table is lower in summer & higher in winter.This is because the rainfall in summer only moistens the dry upper layers which soon gets dried up due to evaporatio...

Most ground water originates as recharge in upland areas,through infiltration.however,it discharges from saturated zones back to surface in low lying areas,usually at the springs/bottom of surface waters.Since,ground water always move towards usually at springs/bottom of surface waters. Since,ground water moves towards lower head,these exist points are always at a lower elevation than the water table where ground water enters the system as recharge. Increasing depth of the earth's crust causes rock porosity & permeability to decrease.pore fluids become hotter & more concentrated with dissolved minerals as depth increases.Deeper than about 10 Km.,the crust has low intrinsic permeability due to high confining pressures & ductile deformation of rocks. Depth shallower than about 6 Km. have high rock permeability & pore fluids can traverse flow paths of continental length scales.For Example:-In Australia,sandstone aquifers convey water for 11...

Ground water is the water found in the pores,avities,cracks & other spaces in the crustal rocks.it is synonymous to phreatic water & is the most important source in any water supply. In it's natural state it is invariably moving which is governed by established hydraulic principles.The flow through the aquifers most of which are natural porous medium are expressed by Darcy's law . Theaore said, law states that the flowrate through the porous media is proportional to the head loss & inversely proportional to the length of the flow path.If the ground water table is assumed to be flowing through a cylindrical aquifer then ground water velocity or Darcy's velocity is defined as the discharge "Q" divided by the total cross sectional area of a cylinder "A". However,the aforesaid calculation ignores the fact that aquifer cross section "A" contains both solid materials & pores.therefore,round water velocity is...

Forest cover gives protection for the soil from compaction by rain,allowing infiltration.some of the infiltration is due to increased root openings.Dense forest provides resistance to lateral flow of water encouraging infiltration.Heavy vegetation provides a layer of decaying vegetative matter hindering lateral flow velocities encouraging infiltration. Organic matter increases soil porosity by aiding soil aggregate formation although porosity also depends on soil particle size,it's packing.Plants however do'nt control the evaporation of intercepted water.Typically 30% - 40% of intercepted water is evaporated from forest when rain is going on. The lowland maritime tropical forests studied by Schelekens et al (1999) and Dykes(1997), loss for higher proportion of intercepted water during rainfall event.Different trees of the forest have different albedo ,hence different amount of energy is available for evaporation,in this manner forest regulate the amount...

During precipitation even part of the rain is intercepted by leaves,stems,branches etc. of vegetation part or all of which is evaporated back into the atmosphere without participating in the land-bound portion of hydrological cycle.This is termed as interception loss. Interception loss=gross precipitation - net rainfall where,gross precipitation includes thoroughfall+stemflow the actors affecting interception loss from vegetation are:- 1)interception loss is higher when rainfalls on dry vegetation because interception storage capacity is higher initially but it decreases as vegetation gets etter,so does interception loss. 2)The air near the ground may not be satuated even during the condensation & rain drop formation high in the atmosphere which may lead to evaporation from leaf surface although interception storage cpacity is filled. 3)Other conditions remaining constsnt,high wind speed will cause high evapo...

The removal of trees reduces the amunt of water intercepted,and hence the amount evaporated back into the atmosphere and more water reches the ground more quickly.the effect of trees on runof depends on the area of forest cleared,type of forest and the climate.Differences in climate make it difficult to compare the effects of removal of trees of different types of forests on runoff. More the frequency of rainfall,longer will be the saturation of the canopy effect on runoff from a wet catchment (eg., in upland Wales) than in the dry catchment (eg., in southern England), the greater the amount of mechanical intervention and the more brutal the method used for deforestation the greater will be the runoff .Removing coniferous forest has the greatest absolute effect on surface runoff but percentage increase may.

"storage' is a hydrological term referring to reservoirs of water contained within the hydrological cycle.These include surface water storage ,soil water storage and ground water storage. Aquifers serve as reservoirs for ground water storage which is controlled by factors like-porosity,specific retention and specific yeild.The amount of water in storage can be determined by the water balance equation:- The mechanism of the storage changes in the confined and unconfined aquifers. There are certain aquifer factors which influence storage :- 1)Porosity; 2)Specific yeild and specific retention; 3)Storage changes in an unconfined aquifer; 4)Storage changes in a confined aquifer. 1) Porosity :-It is expressed as percentage of the total volume of a rock or the soil which is represented by it's interstices or the voids.the formula for the measuring of soil porosity is :- The value obtained from the equation is multiplied with 100 and expre...