Zinwa should also check on levels of siltation in dams

Obert Chifamba

Agri-Insight

NUMEROUS media channels have recently been inundated with stories on the national average dam levels breaching the 88 percent mark, which generated lots of excitement among farmers intending to produce winter crops, especially coming on the backdrop of the projected bumper summer harvest.

This is all happening, thanks to the rains currently pounding the country since the  beginning of the year, which have pushed dams to various filling levels with some, for example, Tugwi-Mukosi, Mushandike and Marovanyati, to name just a few, already spilling. 

Many other dams are most likely to reach the 100 percent full mark should the current rains persist.

Dams have not filled up to spilling levels in recent years, which has forced many winter wheat farmers to scale down their hectarages in line with the water volumes in their sources while livestock farmers on the one hand have even recorded poverty deaths among their herds after water sources dried up. 

Some have had to drive their cattle to water sources situated many kilometres away from their farms.

The Zimbabwe National Water Authority (Zinwa) has done well to keep the nation informed on the situation in our dams, which has helped farmers to make informed decisions, as they do their planning for winter cropping. 

This year some farmers are even targeting to broaden their crop choices and take on board more crops other than wheat.

Horticulture farmers who include those from Murehwa, Domboshava, Mutoko and Seke communal areas will be among the biggest beneficiaries from this season’s persistent heavy rains, as they are most likely to produce many different crops because the water will be readily available even in their garden wells, which  have been drying up halfway through the season in recent years.

But without taking away the glamour from Zinwa for a job well-done, it is also critical for them to also spare a moment and check on the levels of siltation in our dams and if possible, in some of the major rivers too so that when they talk of volumes of water running through the rivers or collecting in dams, they also factor in levels of siltation to give a reflection of the true volumes of water in the country’s reservoirs.

The stark reality on the ground is that upon being established, dams’ water holding capacities are calculated and confirmed but after years of silting those  holding capacities start to diminish hence the need to also establish the levels of siltation. 

Dams that have lots of silt easily fill up but the volumes of water dammed will mislead people especially when the reading is based on the holding capacity set upon their establishment. 

Most of the water will also sink into the soil gathered on the floors of the such reservoirs.

It is therefore crucial for all stakeholders in the agriculture value chain to collaborate and push for the upholding of serious conservation practices by all people who interact with the land at any given point. Farmers are in most cases the biggest culprits, as they sometimes breach environmental laws and farm along river banks, which triggers soil erosion with the  eroded soil finding its way into rivers and dams.

The nation definitely needs to seriously start reviving conservation methods of farming that were used in the past but had been slowly dying out in recent years.

In the past, it was a requirement for all farmers to establish contours in their fields to promote drainage of run-off water from their fields into streams or dams. 

Contours would be populated with grass, which would help keep the soil intact even when there were huge volumes of water moving.

Out of curiosity, I recently sought to establish why and at what point did farmers abandon the practice of contours  in their fields and one of the answers I got was quite exciting. 

Agritex acting director Mr Stancilae Tapererwa explained that many farmers had abandoned the culture during the war of liberation as part of the numerous ways of showing their disrespect for the colonial government, which enforced the practice.

The other reason I also tumbled across was that most farmers no longer found time to work on contours in their quest to concentrate on commercial crops such as tobacco, soya beans and even maize while extension officers who in the past used to make religious follow-ups and supervise their establishment also seem to have shifted their focus to basics of crop production most of the time. 

It is time Zinwa develops synergies with other stakeholders such as construction companies to access the equipment for use in de-silting of affected dams. 

This will help boost the holding capacity of dams so that when they fill up, they will reflect something close to the cubic metres of water they are expected to hold, which also eliminates chances of water running out in the course of cropping programmes.

There are other causes of dam and river silting that include veld fires and wanton cutting down of trees without replacing them. 

These two have in recent years been very instrumental in the washing away of top soil by either running water or strong winds with the soil eventually ending up in water sources. 

This is slowly killing agricultural productivity as most of the land will be left devoid of the rich top soil that is crucial for supporting plant growth.

Conservation programmes should start at the grassroots levels with farmers teaming up and rolling out programmes to save their land and with the help of extension officers who should make sure there is strict compliance to set regulations on saving the soil. 

People who start veld fires should be prosecuted if convicted while those growing tobacco should either use coal or establish woodlots from which go harvest trees for tobacco curing.

Livestock farmers on the other hand need to adopt proper pasture management systems and avoid overgrazing, which leaves the soil bare and without cover to reduce surface erosion that comes with running water when it rains.