Environmental and Health Implications of Irrigation Farming

This article discusses about the environmental implications of irrigation farming. Irrigation farming, due to its nature which involves the drawing of water from its source to the farm has a lot of implications or impacts. These impacts are either of direct or indirect impacts.

An increased evaporation in irrigated areas leading to temperature change of the area and It can as well lead to increase levels of rainfall downwind of the irrigation are some of the direct impacts, while water logging, soil salinization, ecological damage and socio-economic damage are the indirect impacts.

Some adverse effects created are reduced downstream flooding and reduced shipping routes due to reduced water.

Irrigation use in the farm as well lead to health implications like providing good and nutrient filled food for the populace.

Irrigation system makes it possible for food to be available to man even in off-season, provides quantity and quality of food to man and helps a nation be assured of food security. Its use also results in outbreak of pests, disease and proliferation of vectors that can cause malaria, bilharzia and night blindness in man.

The vectors transmit organisms that cause sickness and severe cases leading to death in man. The vectors can be effectively controlled through immunizing of the population against the vector and the use of curative drugs, controlling the population of the vector through use of chemical and educating the populace of how to reduce contact with the vector.

Environmental Implications of Irrigation Farming

The Environmental Impacts of Irrigation – Wikipedia noted that environmental implications of irrigation farming relate to the changes in quantity and quality of soil and water as a result of the practice and use of irrigation.

This stems from the fact that irrigation systems deal with redirecting water from rivers, lakes, and underground sources. This also has to do with how use of irrigation impacts on the natural and social conditions in river basins and downstream of an irrigation scheme or project.

The report also identified with the fact that, on a global perspective, total irrigated land worldwide occupies about 16% of the total agricultural land.

The water are drawn from rivers, ponds, underground water etc. return back to the rivers and this ends up polluting the rivers which of cause may enter the seas and so on, and this may cause some adverse effects on environmental ecology.

An irrigation scheme often draws water from the river and distributes it over the irrigated area. According to the report from a hydrological result, some of the environmental impacts of irrigation are that:

The downstream river discharge is reduced.

The evaporation in the scheme is increased.

The groundwater recharge in the scheme is increased.

The level of the water table rises.

The drainage flow is increased.

In addition, irrigation water used for agricultural purposes may also cause adverse effects / impacts on the surrounding environment and environmental health of the people.

The impacts are caused as a result of the installation and operation of the irrigation scheme. Interesting to point out that these impacts are of two fold. They are the direct and indirect impacts.

1. Direct Environmental Impact of Irrigation

The original sources of irrigation water are rivers, lakes boreholes, etc. and the use of irrigation system means or deals with redirecting water from rivers, lakes, and underground sources. This redirecting of the water has a direct impact on the surrounding environment.

A report of environmental impact of irrigation stressed that the direct impacts of irrigation may revolve around;

Increased evaporation in irrigated areas leading to temperature change of the area and this situation can cause instability in the atmosphere, as well as increase levels of rainfall downwind of the irrigation.

It can as well lead to increase levels of rainfall downwind of the irrigation.

Increased groundwater level in irrigated areas,

Decreased water flow downstream of sourced rivers and streams.

These changes to the climate are a direct result of changes to natural moisture levels in the surrounding atmosphere

2. Indirect Environmental Impact of Irrigation

Irrigation systems also have an indirect impact on the surrounding environment. These indirect effects may not be as immediately noticeable as the direct issues. Additionally, these effects take a longer time to develop and produce longer-lasting changes.

Report of environmental impact of irrigation stated that irrigation can result in the following indirect impacts:

a. Water logging

Waterlogging occurs when the soil becomes oversaturated with water, promoting anaerobic conditions (absence of oxygen).

Such situation results in a condition called anaerobiosis, and this causes plant roots to become unhealthy due to a number of chemical reactions, including a reduction in soil iron and manganese oxides. Obviously, the plants under such environment cannot be able to do well.

b. Soil Salinization

Soil salinization happens when the salt content in soil increases above normal, naturally occurring levels. Irrigation draws a significant amount of water from an area, moving it to agricultural or landscaped lands.

The area that has lost a significant amount of water is often left with concentrated salt levels in the decreased water levels left behind. High salt levels make it difficult for plants to absorb the necessary amount of water and nutrients from the soil.

c. Ecological Damage

Ecological damage can take the form of reduction of water in rivers, deforestation, temperature change, erosion etc. With the practice of irrigation, ecological change amongst other indirect impacts takes longer to occur.

One of the most significant causes of ecological damage is in reduced downstream river flow. When river flow is dramatically reduced, it can lead to disappearing wetlands and flood forest ecosystems.

Additionally, it results in insufficient drinking, industrial, and municipal water supplies. Because less water finds its way into the ocean, coastal erosion may occur, which damages coastal ecosystems such as mangroves and their habitats.

In addition, saltwater makes its way from the ocean into estuaries in increased amounts, which significantly changes the ecosystem and habitat of these water ways as well.

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d. Socio economic Damage

Reduced water flow can also have other less obvious effects on socioeconomic health. Specifically, irrigation may lead to decreased fishing and shipping opportunities.

Water that has been extracted for agricultural purposes leads to reduction in available water in water bodies. The reduction has threatened the local fish populations which causes an imbalance in the natural food chain.

Over extraction of water from water bodies also affects local human populations, who rely on fishing as a source of dietary protein and economic activity.

Where such is the case, the income of such households is greatly affected. Shipping opportunities are also affected as large ships and other water transportation vehicles are left with no alternative.

Adverse Impacts

The use of irrigation system leads to reduced downstream river flow and this may cause any of the following negative impacts:

Reduced downstream flooding.

Disappearance of ecologically and economically important wetlands or flood forests.

Reduced availability of industrial, municipal, household, and drinking water.

Reduced shipping routes due to reduced water.

Reduced fishing opportunities for those communities who depend on fishing activities for their economic livelihood.

Reduction in the protein intake of fish populations due to reduction of fishes in water bodies emanating from reduced water.

Reduced discharge into the sea, which may have various consequences like coastal erosion and salt water intrusion in Delta’s and estuaries.

Health Implications of Irrigation

Irrigation has impacted on the health of man in different ways. A report on Impact of Irrigation on Nutrition, Health and Gender noted the following as issues that can emanate from use of irrigation facility in our environment or farm.

First, the use of irrigation creates salinization which has to do with the presence of concentrated salt in the soil. This condition of the soil deprives plants from doing well and this leads to malnutrition among people of the affected areas.

Secondly, the reduction of water in water bodies results in reduction of fish population, thus creating inadequate quantity of fishes for the people. This condition can lead to a disease condition called Kwashiorkor.

On the other hand, irrigation when properly used leads to;

Availability of or improved access to fresh vegetables and animal sources of food. The consumption of such foods can improve the peoples nutrition and health, particularly that of children.

Consumption of iron-rich foods, such as dark green leafy vegetables, can reduce incidences of anemia. Iron deficiency is a risk factor for maternal mortality and is responsible for many deaths.

Vitamin A – rich foods (such as orange-fleshed sweet potatoes, pumpkins, and so on) can reduce night blindness and susceptibility to illness. Deficiencies of vitamin A and zinc cause have caused many deaths, respectively.

Furthermore, access to greater quantities of nutritious food can reduce incidences of underweight and wasting.

In addition, irrigation interventions may also lead to greater water availability within the household. Access to greater volumes of water can result in better hygiene and sanitation practices and better health overall.

Effects of Irrigation System on Farm Productivity

Both large and small-scale irrigation offers the potential to expand production in the farm. Such expansion can translate into the following:

Availability of food during the lean or off-season. The foods cut across plant and animal sources and they provide man with different nutrients that are needed for growth and development.

Availability of food in good quantity ensures improved benefits in income.

Increase in food also guarantees a nations food security.

During the rainy season, irrigation can pose a risk on production by causing reduction in production due to availability of too much water coming from rainfall and irrigation water.

Effect of irrigation System on Water Cycle

The use of irrigation involves drawing water from different water sources and using it to supply the farm. In doing such, man alters the water cycle through water use demand. Irrigation water quantity is so much that it affects the source from which it is drawn.

This cause changes in water supply by affecting evaporation and runoff. Pumping surface water for irrigation depletes surface water but enhances groundwater. Pumping groundwater for irrigation has the opposite effect.

In a nutshell, irrigation on water cycle has to do with pumping or supplying irrigation water to the farm/field, the supplied water may face evaporation to the sky which will condense in the atmosphere and drop as rain which flows into water bodies and again extracted and resupplied again as irrigation water.

Water-Borne and Water-Related Diseases

Water-borne or water-related diseases are commonly associated with the introduction of irrigation (Report of Impact of Irrigation on Nutrition, Health and Gender).

The diseases most directly linked with irrigation are those vectors (disease carrying organisms) that proliferate in the irrigation waters and they include malaria, bilharzia (schistosomiasis) and river blindness (onchocerciasis).

Other irrigation-related health risks include those associated with increased use of:

Agrochemicals,

Deterioration of water quality, and

Increased population pressure in the area.

The reuse of wastewater for irrigation has the potential, depending on the extent of treatment, of transmitting communicable diseases.

The population groups at risk include:

Agricultural workers,

Consumers of crops and meat from the wastewater-irrigated fields, and

People living nearby.

Sprinkler irrigation poses an additional risk through the potential dispersal of pathogens through the air.

The diseases mentioned above can be caused or may likely occur or be introduced or have an increased impact in irrigation schemes where:

Soil drainage is poor, drainage canals are either absent, drainage canals are badly designed and possibly poorly maintained.

Rice or sugar cane crop is cultivated.

Night storage reservoirs are constructed.

Borrow pits are left with stagnant water.

Canals are unlined and have unchecked vegetation growth.

Effects of Irrigation System on Public Health

Irrigation of farms has actually resulted to some health issues. Impact of Irrigation on Nutrition, Health and Gender pointed out some of the likely diseases. They are:

Malaria: Malaria is by far the most important disease, both in terms of the number of people annually infected, and whose quality of life and working capacity are reduced, and in terms of deaths. Worldwide, some 2000 million people live in areas where they are at risk of contracting malaria.

Among Continents, Africa is the worst hit. Unfortunately, Drug treatment has become difficult due to the build-up of resistance to insecticides by the vectors.

Bilharzia (schistosomiasis): Bilharzia is an infection caused by parasitic worms or blood flukes of certain species of the genus Schistosoma. Adult parasites live in the blood of mammals, but their life cycle requires a phase of asexual multiplication within a fresh-water snail host.

The flukes infect humans who enter their exposed skin in water, usually through swimming, bathing or wading. There exists either urinary or intestinal schistosomiasis.

This disease infection is particularly common in children who play in water inhabited by the snail intermediate host. Severe infection in childhood leads to long-term damage to bladder, kidneys and liver, which may cause death many years after the original infection.

Infection at any age may make people feel unwell and reduce working capacity. The disease is almost as wide spread as malaria, but rarely causes immediate death. An estimated 200 million people are infected and the transmission occurs in some 74 countries.

The type and extent of health complications associated with schistosomiasis appear to vary with species and strain of parasite and by the characteristics of the human population.

River blindness (onchocerciasis): This is another type of disease that occurs in areas where there is practice of irrigation. Irrigation causes wetness of the area that makes the vegetation of the area to flourish and provides hiding for the vector called tsetse fly.

The disease causes sleeping sickness for the victim. This results to dullness / weakness of the victim and reduction in the victims capacity to do work. Severe cases can lead to death.

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The Control of the Water-Related Diseases

Impact of Irrigation on Nutrition, Health and Gender pointed out some of the measures that could help in the control of the water-related diseases. These can be effected in a number of ways, some of which are:

Measures aimed at the pathogens: This involves the immunization of the population and the administration of prophylactic or curative drugs;

Measures aimed at reducing vector densities or vector lifespan: Sure measures would involve the application of chemical, biological and environmental controls that would be able to check the growing rate of the vectors.

Measures to reduce human/vectoror human/pathogen contact: This is an education programme that needs to be taught to the people on how they could reduce or eliminate contacts with the vector. This can be achieved through health education, personal protection measures and mosquito proofing of houses.

Maintaining flood flows: Maintaining flood flows downstream of the dams to ensure that an adequate area is flooded each year, among other reasons, for fishery activities that would guarantee the availability of fishes and its associated products for human consumption and assurance of protein intake.

In summary, this article explains the environmental implications of irrigation farming. Irrigation farming involves the conveying of water from its source to the farm.

Irrigation of farms has some positive effects like making food available in good quality and quantity to the people, makes farming possible throughout the year, thus increasing the wealth or farm income of the farmer and it as well guarantee the nation of its food security.

Contrarily, some of the negative effects are reduction of the flood plains, increases in soil erosion, water logging, and salinization. The use of irrigation facility results in outbreak of pests and diseases and the proliferation of vectors that can cause malaria, bilharzia and night blindness.

Severe cases of this ill conditions can lead to death in man. The vectors can be effectively controlled through immunizing of the population against the vector, controlling the population of the vector and controlling human contact with the vector.

The article also explained the environmental implications of irrigation farming and its direct and indirect impact on the environment and man. The effect of irrigation on farm productivity, water cycle and health implications on man was also studied.

Water-Borne and water-related diseases were considered, from which sicknesses like malaria, bilharzia and night blindness were discovered as some of the sicknesses that can develop from irrigation use. The control of the disease causing organisms were as well advanced.

Read Also : The Irrigation System of Farming: It’s Importance and Effects