Vegetative Waterways

In layman’s terms, vegetative waterways provide a buffer between high velocity flowing water and the soil. This phenomenon works incredibly well, in protecting against soil erosion. Vegetative waterways or grassed waterways are both natural and man-made. These lush green passages are generally found where there is a high-velocity flow of water, especially from upstream. It is important to understand here that these vegetative waterways cannot be made through any kind of greenery. They especially require combinations of venteveria lawsonni, vetivaria, or chrosopogan zizianoids grasses. These combinations of grasses are proven to be immensely effective against soil erosion. These grasses possess longer roots which help them to bind the soil together, protecting it from harsh exterior forces. 

The degree of flow and rush each type of grass can take and handle vary, the flowing chart will make an easier explanation: 

However, there are several conditions associated with the working of the vegetative waterways. The primary ones are that the grasses which are planted in sloping land should be less than 20 percent. Furthermore, the velocity of water should not reach more than 1.8m/s. if either of the criteria is not met then vegetative waterways are not such a good idea in those places. The table presented above gives an accurate description of what kind of cover should be appropriate for various conditions of surroundings, which include the variables of the flow of water and the type of soil. 

Formulae of the Designs of Vegetative Waterways 

There are four basic elements associated with the design of the vegetative waterways:

• Waterway’s Size: the size of the waterways is mainly determined by the runoff rate of the water. This is calculated using the formula

Q=A x V

Here, Q= the tentative/expected rate of runoff of water (m3/s)

A= the area of the waterway (m2)

V= the velocity of water (m/s)

• Waterway’s Shape: There are three main shapes of these waterways, which are; a) Triangular, b) Trapezoidal, c) Parabolic. The Parabolic shape occurs naturally in nature, however, the other two eventually turn parabolic due to sediment deposition over bank erosions or sections of channels. 
• Design Velocity: The velocity of the water can be calculated through this formula: 

• V=1/n x s1/2 R2/3

• Here, V=flow (m/s), 

• n=manning’s coefficient of roughness, 

• s=slope, 

• R= hydraulic radius

• R=A/P

• Here: A= Area of the waterway 

• P=Wetted perimeter 

• Waterway’s location: The perfect location of the waterway is in the area of a natural drainage. This is especially required so that the water gets chances of draining from all sides. 

Inland Waterways Authority of India 

The Inland Waterways Authority of India is a wing under the Ministry of Ports and Shipping in India. The official establishment of this wing was fulfilled in the year 1986. This wing is the legal controller and caregiver of the Indian waterways. The headquarters of this office is located in Noida (Uttar Pradesh). India has approximately 14,500kms of navigable water bodies out of which about 4000 km are canals and more than 5000 km are rivers. The states of Goa, Assam, West Bengal, and Kerala have the highest amount of cargo traffic within the inland waters of the country. The Inland Waterways Authority of India is protected by the Indian Navy in the executive department. Since this department needs to be essentially woke regarding the marine activities within the states, the department takes special care to impose refraining of any suspicious activity from the cargoes which travel in the waterways. 

Irrigation and Waterways  

As abundantly clear, irrigation and waterways are sorts of two faces of a single coin. Irrigation in layman’s terms is an agricultural process where the soil is artificially provided with moisture (water) so that it retains its fertility and helps in the production of crops. However, the purpose which is served by waterways cannot be considered an irrigational process. Waterways protect the soil against high-velocity gushing water, especially from an upstream that crashes on the soil bed with a lot of force and at times washes away the mineral sediments of the soil. This phenomenon not only leads to severe soil erosion but also leads to acute infertility of the soil and makes it incapable of supporting plants around it. 

The purpose of irrigation is to increase the fertility and the productivity of the soil, not so much to protect it. However, the waterways only aim at protecting the soil from erosion.  

Conclusion 

This article focuses on the various aspects of vegetative waterways and also provided a short glimpse of the Inland Waterway Authority of India and its functions. Finally, it provided clear differences between irrigation and waterways.