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Environmental technologies refer to the mechanisms that are innovated to deal with the harmful impacts that result from human activities especially in the exploitation of natural resources (Clavreul et al., 2014). These measures, also known as ‘greener’ or ‘cleaner’ technologies, aim to increase the efficiency of human activities by improving productivity while reducing environmental impacts. Environmental technologies are essential as they focus on maintaining the sustainability of natural resource exploitation for human well-being while protecting the environment. Some of the environmental technologies include technologies for mitigation of soil erosion and technologies for flood control.
Technologies for mitigation of soil erosion
Soil erosion is the movement and displacement of soil particles by means such as water, wind and mass movement (Paz et al., 2016). Mitigation of soil erosion encompasses but not limited to the following measures;
Terraces and terracing
A terrace is an earthen levee built across a steep landscape to seize water flow and hence reduce soil erosion by water (Paz et al., 2016). Terraces reduce the gradient on steep slopes and make it easier to cultivate on the landscapes. They improve the water retention capacity of the landscape improving productivity by promoting soil quality and reducing soil erosion. They also prevent the formation of gullies by redirecting fast flowing water to stable outlets.
Cover crops
Use of vegetation cover can control soil erosion by water and wind. Crops that are used to provide a buffer against raindrop impact on the land as well as slowing the speed of flowing water are known as cover crops (Paz et al., 2016). These crops include common legumes and grasses. These plants are grown when the land is bare and also when main crops are under cultivation. Cover crops such as legumes not only control soil erosion but also increase the nutrient value of soils as they serve the purpose of nitrogen fixation (Prosdocimi and Cerda., 2016).
Strip-cropping
Strip cropping refers to the practice where different crops are grown on different gradients of the land (Paz et al., 2016). This practice serves to reduce erosion by both wind and water. The taller crops serve as wind-breaks while, the shorter crops serve to reduce the speed of water hence reducing erosion by water. An example of strip cropping is the case of soybeans grown in alternate rows with alfalfa.
Agroforestry
Agroforestry is the practice of growing trees together with crops such as maize (Paz et al., 2016). Trees serve as windbreaks protecting both the crops and the soil from erosion. Trees also anchor the soil in agricultural lands by slowing water flow and reducing soil erosion by water. Trees serve the purpose of Nitrogen fixation in cultivated lands as well as adding manure to the soils by virtue of decomposition of fallen tree parts such as leaves. In this way, agroforestry enhances soil aggregation promoting good physical structure of the soils and improving their resilience to soil erosion.
Control of irrigation-induced erosion
Surface irrigation methods cause soil erosion by water if not well maintained. To curb this problem, efficient sprinklers can be introduced in place of surface canals for irrigation (Paz et al., 2016). Sprinkler irrigation eliminates the excess water flow that results from surface methods of irrigation hence reducing erosion.
Conservation agriculture
Conservation agriculture is the approach in the management of agro-ecosystems for improving and sustaining the productivity of agricultural lands (Paz et al., 2016). The approach works on three core principles of minimal soil disturbance, maintenance of plant cover and crop rotations. These principles serve to increase productivity by enhancing soil health and reducing soil erosion. Minimum soil disturbance ensures that soil structure is maintained to improve its resilience against erosion. Plant cover provided by mulch improves soil aggregation, enhancing water holding the capacity of soil and hence preventing erosion by water (Prosdocimi and Cerda., 2016). Crop rotations ensure that essential minerals are replenished in the soil. This retains soil structure in good shape for resilience against soil erosion.
Technologies for flood mitigation.
Floods refer to the phenomenon where water exceeds the capacity of a river, dam, and any other surface water source bursts its banks and overflows to the surrounding landscape (Louck and Van Beek., 2017). Floods may result from heavy rainfall, strong winds over surface waters, tsunamis, or failure of water structures such as dams and levees. The intensity of a flood depends on the damage caused by the overflowing water. High-intensity floods cause damage to infrastructure, cause landslides, displacement of people from their homes or death by drowning. Flood control refers to the various technologies or measures employed to reduce or prevent the adverse effects of floodwaters (Che and Mays., 2017).
Dams and reservoirs
Dams and reservoirs are structures constructed across waterways such as large rivers for purposes of storing water, controlling the flow of water or for flood control (Che and Mays., 2017). A dam or reservoir can be used for the primary purpose of storing water for irrigation or for use in times of water scarcity. At the same time, it can be used to control the flow of water in high rainfall periods to prevent flooding in downstream areas. Dams and reservoirs are engineering methods of flood control. Great maintenance and care have to be observed to ensure that the dams and reservoirs are in good condition to hold water back (Louck and Van Beek., 2017). If not, they can be a hazard to the community as they can break and cause flooding by releasing large amounts of water to the surrounding landscapes.
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Diversion canals
As the name suggests, diversion canals are structures constructed along river channels to divert excess water from the rivers to reduce or prevent flooding (Che and Mays., 2017). Diversion canals constructed along dams and reservoirs redirect water from the dams and reservoirs, especially in high precipitation periods. In this case, then, they reduce flooding.
Floodplain and groundwater replenishment
Excess water can be diverted onto surrounding lands or underground water sources for use such as irrigation especially during times of drought. This method is effective as it not only reduces the risk of flooding but also provides a means for helpfully recycling the flood waters (Che and Mays., 2017).
Weirs and levees
Weirs and levees are low-lying dams constructed along river channels to buffer floods (Haddad et al., 2015). They work in the same way as dams do by retaining water and slowing down the flow of water to prevent it from bursting banks of the rivers and causing flooding. Weirs and levees are sometimes used together with other measures to increase their efficiency. Dikes can be used to lower the risk of flooding.
Retention and detention ditches
Retention and detention ditches are pond-like structures constructed to capture storm waters with the potential to cause flooding downstream (Louck and Van Beek., 2017). A retention ditch retains the water captured resulting in a permanent pool of water. A detention ditch, on the other hand, captures storm-water and releases it at a slow and safe rate.
Coastal Defenses
Flooding can occur along Coastlines. Measures of preventing or reducing such an occurrence include the construction of sea walls and physical barrier islands (Haddad et al., 2015). These structures buffer the impacts of floodwaters on the surrounding environment along the coastline. This way little or no damage occurs in the event of floods.
Resilience and retreat strategies for hazard reduction
The best way to deal with floods is to increase the resilience of structures to floods such that when floods occur, the impacts and costs incurred are minimal (Loucks and Van Beek., 2017). Flood zoning is a retreat strategy for ensuring that flood-prone areas are known in order to avoid construction of useful infrastructure in or around such areas. Insurance of infrastructure that has to be in such areas is also essential to ensure that costs incurred in the reconstruction of damaged properties are minimal.
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