Water management during floods and droughtsRyan Clancy | October 11, 2021
Recently, research conducted into U.S. aquifer water management found that there are more effective ways to manage water than those current prevalent. In particular, irrigation habits and patterns, and their impact on growing food, has been focused on in various regions around the country.
Irrigation can be managed much more effectively in certain humid areas in the U.S., especially toward the East Coast where surface water is much more readily available. Such findings could have a huge impact on where certain foods (or any food) can be grown around the country. No matter what the cause, more intense flooding and longer-term droughts are expected to be more frequent in the future. This is particularly a problem in the western U.S., where there is growing concern about exhausting the water supply, especially for irrigation purposes.
Diverse water strategies across the US
Understanding the direct relationship between the water that humans use and the water (or lack thereof) that the climate provides can lead to streamlining and improving the water management practices that are currently in use. This will lead to more sustainable exercises being used in the future.
The effect that surface water has on replenishing groundwater also plays an essential role in the amount of available water a region has, and also reduces the impact that irrigation has on water resources.
The Mississippi Embayment Aquifer has much higher groundwater pumping rates for irrigation than the California Central Valley, which is regarded as one of the most prosperous agricultural areas in the world. However, data show that the Mississippi Embayment did not experience any groundwater shortages over long periods of observation, despite having high levels of pumping. This was because Mississippi's large stream network collects runoff from thousands of square miles across a large portion of the country. In short, there is plenty of water for the water pumps to irrigate cropland.
In contrast to this, the west of the U.S. has a much drier climate and experiences droughts more often. In the California Central Valley, during wet periods surface water is used for irrigation, and during dry spells groundwater is predominantly used. Since irrigation draws heavily on groundwater resources, irrigation has a huge impact on the amount of available water during droughts. About 30 km3 of the Central Valley is totally depleted of groundwater, which is roughly about the same amount of water as is in Lake Mead, the largest reservoir for surface water in the U.S.
Parts of the Midwest and Pacific Northwest have taken advantage of surface water irrigation in order to preserve the water level in their aquifers, and even allow water levels to increase. This is impressive, as some areas within these regions went through droughts similar to what the Central Valley experienced.
Information was also collected from NASA to show how water and its usage has changed from 2002 to 2017. This study monitored the amount of water in every aquifer in the various areas, including soil moisture, snow, surface water and groundwater. Irrigation records, including the source of the irrigation water, and climate data for each area was complied to compare water level of the regional aquifers.
This created a clear pattern of how the water level in aquifers was changing and how humans were effecting this change. These results area extremely important in effectively managing water resources going into the future.
Learning from water management in India
India is a hybrid economy, where some parts are heavily industrialized and modern while rural communities may still be focused on agriculture and subsistence farming. Groundwater availability for much of the country is dependent on the monsoon season, and in dry years up to two-thirds of farmers may struggle to water their crops. As a result, the country is dependent on imported agriculture, which is expensive and complicates the self reliance of the world's second most populous nation. Additionally, up to 80% of groundwater is used for agricultural purposes, and cities and regions are threatening to completely empty groundwater reserves.
India adopted the National Water Policy in 2002, which highlighted the need and plan for surface and groundwater development, project planning, flood control and irrigation. Large programs have been introduced to improve surface and groundwater resources and develop the irrigation infrastructure through many water management projects in river valleys.
It was accepted that irrigation was vital for the increased production of grains, which made the country less dependent on imports. India prioritized standing groundwater for irrigation as the second most critical need -- only after drinking water -- but ahead of hydropower and transportation.
A government data information and agricultural service was established to help farmers predict and react to seasonal climate, and is pushing farms to adopt drip irrigation. This plan also called for additional rainwater harvesting, and groundwater and standing water rationing, as needed. However, the government balances this against local needs for water.
Additional research has indicated that India does in fact have enough water to meet all its needs, but the country at large needs to be smarter and more considerate about water it uses.
Flood control was identified as another important area, with flood cushions and embankments needing to be installed. Since the inception of the National Water Policy, about one third of the country’s flood-prone areas are now reasonably protected against floods. Additionally, dams and reservoirs are now able to store more water. There will be no absolute solution to floods, no matter how much flood control and protection is put in place. However, the flood control efforts have prevented large scale damage, and the flood forecasting and mitigation made possible by these efforts will play a vital role in saving lives in the future.
This includes cyclone forecasting; tropical cyclones form over warm sea where there are intense low-pressure systems. They can cause huge amounts of damage with heavy rains, storm surges and strong winds. Cyclones must be monitored and adequate warnings given to the necessary areas. A forecast scheme and analysis of cyclones has been worked out, using satellites to predict where and when cyclones can form.
India is still learning how to optimize its resources, but it is proving to be a global leader in resource allocation, albeit decades after mismanagement.
How do you think water can be conserved even further to improve irrigation and in turn food production around the world? Do you think optimizing irrigation will be enough? Engineering360 would love to hear your thoughts in the comments below!