Hydraulic ram pumps and Sling Pumps

figure 2.5Total catchment per annum = 135 675 litres. About 136 m³ of rainwater can be caught within a yearfrom 450 mm rainfall.The size of the chosen reservoir depends on the lowest inflow (see Fig. 2.5) and also on the groundspace available. Block B has a gutter height of 3.00 m, Block A height of 3.30 m. The lowest inflowwould come from Block B. Since gutters and downpipes must slope towards the inflow, the heighthas to be calculated. For the gutters a 0.3% slope is the minimum requirement (equivalent to 3 mmper metre). Block A has a gutter length of 20.0 m (20 x 3 = 60 mm), a downpipe with a minimumslope of 10% (10 mm per metre) to the middle of the gable wall 5.0 m, which means another 50 mmfor sloping.We add the 60-mm slope of the gutters to the 50-mm slope of the downpipe resulting in 110 mmand add 15 mm for the distance from the gable wall to the tank inflow, resulting in 125 mm. Forimprecise workmanship, measuring faults etc. we assume a total of 200 mm. These 200 mm haveto be deducted from the height of 3.00 m between gutter and ground. This final measurement is2.80 m and indicates the lowest inflow level and at the same time the filing height of the tankassuming that the bottom of the reservoir is level with the ground. The catchment capacity is about135 000 litres at the most, with a filing height of 2.80 m. Table 5 shows a filling height of 2.65 m.With this filling height, we can build a reservoir with 133 000 litres with an internal diameter of8.00m.20