The Soil and Its Properties
The soil is the topmost layer of the earth's surface, the outermost layer of the crust, and has properties that dictate a multitude of influences, such as water flow, percolation, and the types of plants that can thrive. These characteristics include soil texture, water holding ability, and Ph.
Artificial Groundwater Recharge
Artificial recharging of the soil is a method in which the percolation of water into the deep ponds is increased by artificial means, such as the use of harvested water and the redirecting of water to some areas (Water.usgs.gov). The soil properties that define the artificial Groundwater Recharge are discussed in the following section.
Soil Texture
This is defined as the softness or coarseness of the soil to the touch such as after rubbing it in between the fingers. Sandy soil has a rough texture while clay soil is soft to the touch and thus is said to have a smooth texture. The former is characterized by having a high drainage capacity with poor capillarity while the latter has excellent capillarity and poor drainage. From this perspective, we see that the sandy soil has the ability to allow water to pass through quickly as opposed to clay soil thus it facilitates artificial groundwater recharge and allows water to accumulate at the bottom in aquifers. Additionally, the water is held within these soils due to the poor capillary action of the soil. In a nutshell, the more airspaces the soil has, the less water it shall hold and the poorer its rate of capillarity shall be, and thus it shall be an excellent drainage medium for water into underground reservoirs.
The Soil Structure
This is the arrangement of the soil particles that are sometimes referred to as soil aggregates. Porous spaces or solids may separate these particles. The soil structure is categorized depending on the strength of cohesion, size, and shape of the granules. The soil structure influences various factors such as the ease of air movement in the soil, water percolation, and infiltration. These factors, in turn, have an impact on how fast or slowly the water infiltrates into the soil; a porous soil shall have more air spaces and thus allow for water to infiltrate to the reservoirs below while compact soil shall prevent or significantly slow down the infiltration of water thus giving it time to drain on the surface as runoff and or evaporate back into the atmosphere. Last but not least, compact soils have the ability to retain water and thus allow for surface water accumulation that exposes the water to evaporation longer. However, there is more to soil structure as discussed in the subsequent section (Megphed.gov.in).
A Granular Soil Structure
A granular soil structure has enough organic matter and is characterized by having ample space in between the granules which make it more permeable to water. With relation to artificial underground water recharge, in areas where the aquifer has the soils with such structure overlying them, more water tends to percolate due to the permeability of the soil. Secondly, there are the columnar soil structures that consist of sodium which has the properties of dispersing that spoils the soil structure, greatly inhibiting water and air movement thus making the soil moderately permeable. Therefore, aquifers that are overlaid with such soil structures have moderate levels of underground water. Thirdly, is the Platy soil structure characterized by the least amount of pore space within the soil granules and in most cases, these soils are compact in nature. This makes the soil to be lowly permeable as well and have poor drainage. Thus, if soils with such structure are overlying an aquifer, the chances of precipitation infiltrating and percolating into the underground to form underground water are minimal thus we shall have less artificial underground water recharge in this region. Last but not least, are Irregular Soil structures which have no definite soil structure and tend to be a blend of various structures. They are hard to describe, as they do not conform to any form of shape or size. Soils with such soil structures have the least permeability. Therefore, such regions record the lowest level of underground waters as compared to the previous soil structures (Pan & Weinan).
Water Holding Capacity
Different soils have diverse abilities to hold or retain water, which affects how water drains over the surface of the soil and infiltrates into the ground. The water remains in the pores and on the surface of the grains that are aggregated. The variability in the holding capacity relates to the soil texture. Sandy soils, for instance, despite the fact that they are easy to cultivate, cannot hold water for long and thus, water will infiltrate into the underground to become a part of the underground water. Contrary to the sandy soils, clay soils do have small pores that allow the storage of water, meaning they can retain water for quite a while, which can be used by plants. This makes them the best soils in terms of high water holding capacity. The less porousness makes it have low infiltration and consequently low percolation, which results in less water in the underground aquifers (Megphed.gov.in).
The pH Level of The Soil
This pH refers to the level of acidity or alkalinity of the soil and affects the permeability of water in soil due to the mineral components. This aids in deciding the best suitable crop planted in that region, which indirectly determines how and at what rate the water infiltrates into the soil. A soil with heavy vegetation cover slows water flow and thus results in more percolation, while scarce vegetation cover means rapid runoff and less infiltration. Some crops thrive well in acidic soils and others in alkaline soils. The pH scale value has a range of 1-14. From this range, soils that fall in the range of 3-7 are acidic, while those above seven are alkaline soils, and a pH scale of seven is neutral. The lesser the scale, the more acidic, while the greater pH value, the more alkaline it is. This alkalinity and acidity of the soils come about due to the mineral components of the soils. There are hard metal minerals that are insoluble and other minerals that are more soluble; therefore, the more soluble a mineral is, it means the water can dissolve the minerals and percolate or infiltrate with the minerals into the underground aquifers, while the hard-mineral components that are insoluble are less porous, thus less permeable. This influences the amount of water infiltrating and percolating into the ground. Thus, the lesser the permeability, the minimal underground water in the aquifer (Soil-net.com).
Conclusion
From the above discussion, we learn that indeed there is a relationship between the soil properties and the presence or the amount of water available in the artificial underground recharge. This is highly attributed to the fact that for water to be in the aquifers, there must be percolation. All the soil properties affect the permeability of soil, as well as the underground water recharge.
Works Cited
- Megphed.gov.in. "Artificial Ground Water Recharge." 1 May 2017. megphed.gov.in. Document. 1 May 2017.
- Pan, Weinan, et al. "Characterizing Soil Physical Properties for Soil Moisture Monitoring with the North Carolina Environment and Climate Observing Network." Journals Online (2012): 933-943. Journal.
- Soil-net.com. "Properties of soil." 1 May 2017. soil-net.com. Document. 1 May 2017.
- Water.usgs.gov. Artificial Groundwater Recharge. 1 April 2002. Web. 2017 May 2017.
