Soil Water Table: Is the worst over for the dry season?

Many Nigerians depend on the soil water table for their primary water source, although only a few understand the mechanism behind their water source. Gone are those days when government-supplied pipe-borne water represented the populace's primary water source. There used to be a country.

Nowadays, a large percentage of the populace depends on boreholes or hand-dug wells for their water source. For those that are rich enough, a pumping machine is inserted into the borehole or well and a reservoir is placed on an elevated platform. The reservoir is then connected to the household's plumbing network to serve as the source of water.

Those that are not so rich resort to fetching water manually from wells using containers tied to ropes. Whatever the case may be, this section of the population depends on the water table level of the soil for their regular water supply.

The soil water table is the level below the surface of the ground where the soil is saturated with water. It's like an underground lake, and the height of the water in that lake can change depending on factors like rain, evaporation, and the amount of water being taken out by plants. If you were to dig a hole down into the ground, you would eventually reach the soil water table if you kept going past the dry soil.

Knowing the level of the water table is important for things like agriculture and building construction because the water table can impact how easily roots can absorb water, or how well a foundation can stay dry. It is also important for those of us that depend on it for our household water supply. However, many of us don't pay heed to this factor when digging our manual wells. Borehole drilling services often carry out surveys to determine the level of the water table before locating a well.

^{The manually dug well that serves my household with domestic water.}

We are currently in the dry season as far as the Nigerian climate is concerned. It started around November last year and is expected to last until February ending. A little rain is expected in between and we've had two (one light and one heavy) already between January and now as far as my locality is concerned. A variation is expected nationwide however with some regions (coastal areas) having a lower dry season and some regions experiencing a longer one.

The bottom line is, the water table level of the soil usually goes down during the dry season depending on the severity of the dry season. Since the dry season commenced, my household has been having a little challenge with water. The pumping machine in our manually dug well is a submersible one and the implication is that it stops pumping once the water table level goes lower than the machine.

Even though it has been a challenge, we are still among the lucky ones because the water level comes up every now and then during the day and the machine is able to pump a bit. My hope is that the situation will not get worse before the dry season ends and the rainy season commences. A few weeks into the rainy season and things will be back to normal.

Factors affecting water table level

The soil water table level is a dynamic and constantly changing aspect of the environment. An understanding of the factors that affect the soil water table level will go a long way in the management of environmental water resources. Below are some of the most important factors that influence the water table:

Precipitation: The amount of rain or snow that falls on an area has a significant impact on the water table. If there is an increase in precipitation, the water table can rise, and if there is a decrease in precipitation, the water table can fall. In our own case, the water table level decreases significantly during dry seasons due to a significant decrease in the amount of precipitation.

Evapotranspiration: This refers to the process by which water is lost from the surface of the soil through evaporation and transpiration by plants. When the rate of evapotranspiration is high, the water table can drop, and when it is low, the water table can rise. Dry seasons are usually characterized by strong sunlight and high temperature. These factors accelerate the evapotranspiration rate from the soil and further lower the soil water table in addition to reduced precipitation.

^{The water reservoir. A submersible pumping machine pumps water from the well into the tank. The tank then supplies water into the house.}

Groundwater pumping and Recharge rate: The pumping of groundwater for irrigation, drinking water, or other purposes can have a major impact on the water table. The recharge rate, on the other hand, refers to the rate at which water is added to an aquifer, either from precipitation or from other sources.

The recharge rate is a crucial factor in determining the water table level, as it determines how quickly the water table will rise or fall. If pumping is done at a rate that exceeds the recharge rate of the aquifer, the water table will drop. This is exactly what is happening in our own case. Once the water recharges a bit, we are usually able to pump. Once the pumping rate exceeds the recharge rate, water stops pumping.

Topography: The shape of the land surface can also influence the water table. In areas with a high water table, the land may be flat, while in areas with a low water table, the land may be hilly or have a steeper slope.

Soil type: The type of soil in an area can also affect the water table level. Soils with high permeability (the ability of water to move through the soil) will allow water to move more easily through the soil, which can result in a higher water table. Conversely, soils with low permeability will result in a lower water table.

Land use changes: Changes in land use, such as urbanization or deforestation, can have a major impact on the water table. Urbanization can result in increased runoff and decreased infiltration of water into the soil, which can lead to a drop in the water table. Deforestation can result in decreased evapotranspiration and an increase in the water table.

It is obvious that the water table level is affected by a complex interplay of natural and human factors. Understanding these factors is crucial for managing groundwater resources in a sustainable way and for avoiding problems associated with groundwater depletion. In our own case now, the dry season seems to be playing the biggest role in our water challenges. With two showers of rain in quick succession, we are hoping that the worst is over for the dry season.

What do you think?