Siltation of water bodies threat to agriculture

10 Sep, 2017 - 02:09 0 Views
Siltation of water bodies threat to agriculture File picture of Umzingwane Dam

The Sunday News

File picture of Umzingwane Dam

File picture of Umzingwane Dam

Vincent Gono, Features Editor
The success of the Government’s Command Agriculture programme whose tentacles are spreading to include fish and livestock farming has been pinned on the availability of adequate resources, chief among them water.

Mindful of this resource and importance, those who spearheaded the programme were fast to announce at the launch of the programme that inputs would be availed to those close to water bodies so that in the likely event that rain water becomes inadequate, irrigation would come in handy to see the crops through to harvest time.

And as in fish farming under Command Agriculture communities were encouraged to group themselves and make use of the water bodies that are close to them.

The emphasis on water speaks volumes of its importance as a critical ingredient in all agricultural activities. It is the common denominator and the lack of it means there is no production to talk about. The bountiful agriculture season that the country is gloriously basking in currently is therefore partly courtesy of the coincidence that most parts of the country received normal to above normal rainfall which saw even communal farmers who were not part of the Command Agriculture initiative getting a splendid harvest.

This gave the country the impetus to continue the programme and even expand it from crop farming to livestock and fish farming although water availability remains critical. However, the initiative might suffer a setback if nothing is done to de-silt the water bodies that the country has that are heavily silted with reports that the country has set aside $7 million for de-siltation, an amount far below the required figure.

The threat posed on agriculture by siltation can therefore never be overstated. It is a menace that remains lurking in the background and if overlooked may give sceptics and pessimists of the programme something to laugh about.

Siltation gives the false impression that there is much water in the water bodies when there is little thereby making planning for the said water false as much of the space would have been taken up by silt.

This is evidently clear when one looks at the amount of water that the country received this year that was historic and how most rivers have become dry barely a few months after. Despite the above normal rainfall received in most parts of the country, river beds are showing no signs of the precious liquid, threatening lives of both humans and livestock.

Zimbabwe National Water Authority (Zinwa) corporate communications manager Mrs Marjorie Manyonga told the Sunday News in a telephone interview that they were worried about the levels of siltation in the country’s rivers and dams.

“Siltation is really a cause for concern to us as a national water authority. The country’s rivers and dams are heavily silted and it greatly affects water yields and water holding capacity of our water bodies,” she said.

Mrs Manyonga said the major cause of siltation could be attributed to land degradation due to anthropogenic activities. She added that strategies to minimise siltation including integrated river basin management and sustainable land use approaches were being pursued to combat the problematic issue.

“Efforts are being made to de-silt the dams and rivers. We are also engaging the communities on sustainable land use together with the Environment Management Agency (Ema). In fact we are not alone in this. It’s an approach that is multi-sectorial. We are engaging the ministry of mines too,” said the Zinwa corporate communications manager.

She confirmed that if let to go on unabated the scourge of siltation was likely to derail efforts by the country to engage in more agricultural activities as well as affect dams that were providing water to cities and towns. She said the most affected catchments were that of Save, Sanyati and Umzingwane, adding that the country remained quite susceptible to gully erosion.

Reports are however, that Save alone needs close to US$1,5 million to de-silt. To reduce siltation and clogging of water bodies, she said, the best practice was to maintain the riverine vegetation undisturbed. She bemoaned the lack of adequate financial resources and equipment to start the de-siltation work saying the drag lines were not enough.

Stream bank cultivation, deforestation and illegal mining in most parts of the country are the major drivers of siltation affecting streams, rivers and dams and impacting negatively on the country’s holistic approach to mitigation and adaptation to climate change.

The trend where stream bank cultivation is rampant has been noted both in the rural and urban set up of the country and is driven by the search for wetness or water provision as well as fertile soils.

This is despite such legislation as Section 113 of the Environmental Management Act (Chapter 20: 27) as read with section 20 of Statutory Instrument 7 of 2007 (Environmental Management (Environmental Impact Assessment and Ecosystems Protection) Regulations) which prohibits cultivation and introduction of exotic plants and animal species into wetlands and land within 30m of a public stream, river or water body. The prohibited activities require a special licence from EMA for one to work in the riverine zones.

According to Ema, they have conducted an inventory survey of all the affected rivers by stream bank cultivation in all the provinces. The inventory was carried out to ascertain which rivers in particular are affected, to what extent and the exact location.

Community meetings with communal farmers are being done throughout the country, with particular attention on the areas with affected rivers identified in the initial inventory exercise. These community meetings are done together with traditional leaders to raise awareness on sustainable agricultural practices such as the growing of crops at least 30m away from the bank of a river, handling of agro-chemicals to prevent water pollution and fire management.

These community meetings will, according to Ema, culminate in the development of Local Action Plans for resource mobilisation. Ema said it was contributing to the Action Plans through the formation of consolidated gardens. The consolidated gardens are a sustainable livelihood option, whereby communities come together forming gardens with different crop varieties instead of setting the traditional gardens and practising stream bank cultivation.

Environmentalist who is also Environment Africa country director Mr Barnabas Mawire said if not managed carefully the country risks having fewer rivers, adding that it posed serious dangers to communities who depend on the various water bodies for domestic use of the resource.

“Siltation is a problem that most of the country’s rivers are faced with and it surely needs urgent attention from the sectors involved. It is whereby silt or soil deposits occupy the space that should be occupied by water, reducing the amount of water that the particular water body should have.

“What it means therefore is that there will be far much less water in the river or dam and it promotes growth of aquatic life and in some cases the river will just disappear. This is bad for fisheries and is usually a result of catchment area mismanagement. There is a need to come up with catchment area initiatives where the discourse of rehabilitation of catchment area should be central to the whole issue,” said Mr Mawire.

He urged Ema to enforce the legislation that prohibits stream bank cultivation and deforestation and gold panning activities.

Mr Mawire said such things as overgrazing, veld fires and rampant cutting down of trees by new farmers should be treated as serious threats to the environment and relevant legislation should be evoked to avoid long term environment catastrophes.

“There is need for rehabilitation of catchment areas to arrest run off. People should also take seriously to conservation agriculture practises and avoid cultivating on sloppy landscapes. I think these if enforced by the relevant authorities and other initiatives as avoiding gold panning, deforestation, overgrazing and stream bank cultivation may help preserve the country’s water bodies and enhance the Command Agriculture programme,” he said.

He also urged a multi-sectorial approach saying this was not the work of a single Government ministry but everyone should be on board, including communities from where the button starts and ends.

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