G M TODD IRRIGATION
Farm in Nelspruit

Through our professionally trained staff, and personalized service, we have been involved in the development of the Irrigation farms in and around Nelspruit Mpumalanga, stretching into Maputo and Gaza Province’s of Mozambique. Todd Irrigation provides a complete solution to all your water and de-watering needs. Todd irrigation has unsurpassed expertise throughout Southern Africa, to select the right pump for you. The G.M Todd Irrigation takes the following approach to the design, supply and commissioning of an irrigation system. Taking the above parameters into account we work within the available budget to best meet our client’s needs. Certainly one of the most important factors concerning one’s borehole is its management. It should be stated clearly that a borehole test where only the yield and no water levels has been measured does not mean anything in terms of borehole yield (strength), and is at best a test of how the pump equipment performs. There are a number of aspects that needs to be taken into consideration when testing a borehole, there are two important rules that needs to be kept in mind when determining the sustainable yield I.e.: The total abstraction from a borehole should be less than the natural groundwater recharge, and secondly, a borehole should be pumped in such a manner that the water level never reaches the position of the main water strike (normally associated with a fracture). To estimate the sustainable yield and hydraulic performance of individual boreholes for water supplies. To assess the hydraulic characteristics of the aquifer to determine groundwater resources. Test pumping consists of pumping a borehole at a specified rate and recording the water level (and therefore the drawdown) in the pumping well as well as in nearby observation boreholes at specific time intervals. There are three primary types of borehole yield test’s, step test, constant rate test and a recovery test. This type of test is particularly useful to determine the effectiveness of the borehole, but not too useful in determining the long term sustainable yield of a borehole. The discharge is kept constant for the duration of the test, and water levels are recorded in the pumping borehole as well as observation boreholes (if any). The time-drawdown data obtained from the CRT is then analyzed for quantitative (estimation of transmissivity, storability and hydraulic parameters) and qualitative analysis of borehole and aquifer response to pumping. The analysis provides useful input to assess the sustainable yield of individual boreholes and the potential of aquifers. in this test, recovering water levels are measured in the pumping borehole immediately after the CRT, when the pump is switched off. This recovery test is very useful in qualitatively assessing the pumping effect and possible dewatering of aquifers that may result due to the limited extent of an aquifer. An important aspect of a borehole yield test is the monitoring of the water quality as pumped from the borehole. A water sample is generally taken at the start of the test as well as at the end of the test for full chemical analysis, while the electrical conductivity and temperature is normally monitored with the water level for the duration of the test. The determination of a sustainable yield will normally take this information into account. The water quality is also of importance to determine whether it is suitable for domestic, irrigation or industrial purposes. An example of this importance for domestic purposes is the nitrate content of water. Remember that the pump supplier can only work on the information that the owner of the borehole provides and can thus not be held responsible for pump or borehole failures if the borehole is over pumped.