Sewer Rehabilitation, a promise to a cleaner Bulawayo...

A stench meets you as you walk around the high density suburbs in Bulawayo; it is the unmistakable smell of sewage. The sewer lines are blocked resulting in sewage is not moving to the sewer treatment plant. Sewage then flows out of the manholes to the streets then to people’s houses.


Dabane Water Workshops, working together with the Bulawayo City Council and World Vision have started the de-choking and rehabilitation of the sewer lines using a jetting machine for de-choking. It is not a one day job; so far the Dabane team has started working on the Magwegwe sewers, mapping the over 2000 manholes, so as to make the process easier.


a sample of mapping manholes using google earth( magwegwe north)


The blockage of the sewer system has been a result of people throwing in large objects into the manholes, such as heavy rocks, stones and even dead animals. In some instances tonnes of sand have been removed from the de-choked manholes. Whether the incidences are done on purpose or through ignorance one would never know. However, it was suggested that some of these blockages are done on purpose for irrigation, as trenches were seen starting from the burst manholes leading to their small vegetable gardens in the veld.

sewage flowing onto the streets into people's yards

Workshops have been held on sanitation, to educate the communities about the hazards of blocking the sewer lines and of having sewage flowing in their streets and yards. A lot of work has been put into communicating with residents on the danger of throwing heavy and large materials down the manholes. The results of these workshops are a bit slow to show because there are some areas where the blockages still continue, but we are hopeful that before the end of the year sewer lines would be clear.

A clear and unblocked manhole

The community is reminded to stop putting heavy materials into the manholes and that these sewers are for the good of the community.

RAINS OF HOPE- Siqala ngamanzi

Water was becoming scarce in late October and November because of the low rainfall. Although people had other means of getting access to water, thanks to the sand abstraction pumps introduced by Dabane, it was not nearly enough. Areas such as Gwanda and Beitbridge known for their high temperatures were in dire need of a miracle, as the water table became lower their needs for water were becoming higher. A high yielding dam in Gwanda called Dambashoko was running low on water and the area in which it covered was now covered with cracks. The water was muddy and unsuitable for drinking.
 Animals could be seen standing in the distance not attempting to go near the water although evident that they were thirsty. The herd men who were observing us with curious eyes, moved closer to tell us that it was not really safe for them to bring their livestock to drink in the river. They revealed that on a daily occasion they find some cows or even donkeys stuck in the mud and weak from struggling to get out, that eventually they have to kill them. Sometimes they even find them dead.



the once highyielding dam..(Dambashoko dam in Gwanda)

 

The situation is critical in rural Matabeleland South, the residents have resorted to traditional sources of water such as shallow wells and water rationing, whereby the boreholes are disconnected till a certain time and each family is allowed to draw only 40litres of water a day.

We are however hopeful that with the heavy rain we have been recieving in Zimbabwe, that there will be an improvement in the water situation in Mat South.

To date, these are the local dam levels according to how full they are:

Dam                              Purpose                                 % full
Beitbridge 1                 Water supply                            75.1%
Mtshabezi                    Water supply/ Irrigation            101.2%
Insiza                           Water supply/ Irrigation               87.6%
Khami                           Irrigation                                   93.5%

Let’s restore our pride – Keep Bulawayo Clean

Dabane trust therefore has taken the initiative to help educate the communities and to help in the clean up campaign it will improve their living conditions thus becoming sustainable as the communities will realise the benefits of leaving in a dirt free environment.

The targeted area was the Magwegwe North terminus in Bulawayo where public transport operates and where there is a shopping complex with a number of vendors selling fruits and vegetables outside. It was important to clean this area so as to avoid or reduce air and environment pollution. An average number of about 85 people including the youth, the old aged, the working class and the disabled were involved in the clean up. 70% were women and 30% were men.

 Dabane provided hand gloves, disposal bags and a heavy duty truck while the community provided their own tools which included; 5 wheel barrows, 7 racks, 10 shovels, 6 slashers and two picks. These were used to clean the terminus and made the job much quicker. Dabane also provided promotional material of T-shirts and hats that were meant to promote the campaign. The communities sang and danced as they carried on with the clean up.

10 men (mainly youths) were assigned to go and help with the disposal of the refuse at the sanitary landfill site. During the cleanup, health workers, the Bulawayo city council representatives talked to the public about the purpose of the cleanup and the importance of keeping our surroundings clean and saving water.

Market linkages

Will Market linkages programme improve the livelihood of Gwanda communities?

Market Linkages are an innovative initiative, which are under PRP II. The aim is to improve the income generating capacities of 26 garden groups and Conservation Agriculture beneficiaries in Gwanda district. The programme capacitates the farmers in value addition through food processing and preservation and will link them to markets in Filabusi, Bulawayo and Gwanda. A value addition and processing centre is to be constructed at Nkwidzi business centre to assist farmers in processing and selling their produce.

 Project officers have held meetings with the relevant local government offices, local leaders and other stakeholders such as AGRITEX, Environmental Health Technicians and communities in Matshetshe, Datata, Mzimuni and Shake wards to define and agree on roles of each stakeholder. Community members from the four wards have selected four seven-member committees that are expected work together to ensure that farmers regularly send their produce to the centre and also play an administrative role. In three wards, the seven member committee consists of three men and four women, while in Matshetshe it is made up of three women and four men.

Alternative Sand abstraction technologies.

Five more alternative technologies have been introduced in Dabane trust's programmes. These have been devised in a in order to cater for those areas that cannot accommodate the well point technology. The alternative technologies include:

1. Caissons
2. Sand dams
3. Tube wells
4. Bio-sand filters
5. Underground tanks

Caissons

Caissons as typically larger structures than well-points or infiltration galleries which are installed directly into the riverbed or into alluvial riverbanks where there is low permeability. Lower sections of the caissons are permeable so that water flows from the sediment into the caisson and eventually creates a graded filter around the base of the caisson.

A caisson can be considered to be a well shaft that does not reach the surface. It is generally covered by a slab with a narrow diameter connection either vertically to the surface or horizontally to a sump on the riverbank. Conditions necessary for Caisson Construction include fine aeolian sands, low permeability and low porosity.

Sand dams

The type of riverbeds that are most convenient for sand dam construction have hilly and stony catchments that produce coarse sand where up to 350litres of water can be extracted from 1litre cubic metres of sand. Such rivers are suitable for sand abstraction projects. The main purpose of sand dam is to increase the volume of sand and water in riverbeds by putting a barrier (dam wall) on a river channel.

Listed below are the conditions that are suitable for sand dam projects:

• Two high riverbanks to enable the wing walls to keep over-flowing flood water within the spillway and not flowing over the riverbanks
• Dam walls should never be built on fractured rocks or large boulders because such walls cannot be made water tight. Water will always seep out between the boulders.
• Riverbeds with fine textured sand originating from flat land are also unsuitable for sand dams because less than 5% of the stored in the voids between the sand particles can be extracted.
• Water- indicating vegetation, that requires water all year round, should be growing on the banks where the reservoir will be located as proof of the riverbed capacity to store water.

Bio- sand filter tank

This can be defined as an innovation on traditional slow sand water filters, specifically designed for intermittent or household use. The filter container may be made of concrete or plastic and is filled with layers of specially selected and prepared sand and gravel. The filter is a simple container that encloses layers of sand and gravel, which trap and eliminate sediments, pathogens and other impurities from the water.

The bio- sand filer tank operates in a way that contaminants are removed to ensure maximum possible treatment efficiency.

Bio-sand filter tanks that are used to purify water in the rural areas...







Rainwater Harvesting Tanks

These are rainwater catchment systems, which can seldom compete directly with conventional municipal supplies in terms of cost, reliability and quality. Although the cost of installing rainwater catchment tanks is high, the catchment and delivery systems (gutters, downpipes, etc) are normally already present in the urban context.

Roof tops can act as catchment areas but some key points should be considered when selecting a site for a tank. They include:

• Tanks should never be located near toilets or pit latrines.
• Be located well away from any waste-disposal facility or other source of pollution or contamination which may threaten the quality of the stored water.
• Carefully sited with respect to the possible damaging effect of soil erosion.
• Sites where substantial surface runoff may occur in storms should be avoided.
• Tanks should be located so they can collect water from as large a roof area as possible e.g. between two buildings.
• Tank should not block walkways.
• Water tanks should be located at a minimum distance of 900mm from the wall of their roof catchments.

Water from sand rivers

A book has been published on sand-abstraction and issues related to it.
Issues covered in this edition include:

• sand-rivers
• site identification and selection
• abstraction methodologies
• installation technology
• pump technology
• pumpselection

all this and more from the book, Water from sand rivers...

by Hussey S,W. WEDC , Loughborough university(2009)

get yourself a copy: resourcecentre@dabane.org

Dabane-water workshops

Sand Abstraction technology

Dabane Trust has pioneered a simple, low cost water abstraction system that is suitable to use in arid and semi-arid areas. In these areas the rivers flow only for a few days in each rainy season. However many of them have a significant depth of sand which can retain water in sufficient quantities to provide year round water. Because the water is held in the sand it is naturally filtered and is thus clear, fresh that is clean enough for even safe domestic use. Over more than fifteen years Dabane Trust has developed simple hand pump systems to draw water from these ostensibly dry rivers, not only for household use but also in sufficient quantity for livestock water and for small-scale irrigation of basic vegetables.