Table ESBC scenario: Sources of additional water and related annual average volumes required to cover the sum of the individual nodal deficits in each IUA for current conditions (million m3/a) WMA portion IUA Total nodal deficits under ESBC (million m3/a) From From Surface water scheme From TMG Aquifer Action to supplement ESBC shortfall under current demands. Breede B5 - - none H16 - - none H17 - - Although IUA in surplus there is a 0.5Mm3 deficit at G50F. Brought about by a decreasing surplus between G50D (in F10) and a smaller surplus in G50F. SO DO NOT COST F10 - - IUA in surplus and no individual nodes have a deficit. A1 - - none A2 + A3 4.2 1.7 2.5 Must treat A2 and A3 as one due to IUA delineation. Although there are deficits in the ESBC most are the result of subtracting large upstream surpluses and are not meaningful. One node (Niv11) in H40C (GW= 1.7Mm3) is in deficit of 4.2Mm3. Cost 1.7Mm3@R5 and 2.5Mm3@Regional Scheme (R13). Used some of surplus in A1 (20Mm3) to put ESBC in positive B4 - - none F9 - - none F11 - - Although the IUA is in a deficit of 72.6Mm3 this arises from accounting for large upstream surpluses that get reduced in IUA F11. The IUA is still in a surplus and has no individual nodal deficits. Gouritz E8 - - none C6 - - none D7 2.8 2.8 Although the IUA is in surplus there is a deficit at J33F of 1.6Mm3. GW availability is 1.49Mm3. Get deficit of 0.11 from J35A (GW=5.6Mm3). Also a deficit of 1.2Mm3 at J35D. GW availability is 4.92Mm3
B4 18.9 6.9 12.0 - IUA is in a deficit of 18.92Mm3 at Nv6 in H60F with GW=6.88. So cost at 6.88Mm3 @ R5 and the rest (12.04Mm3 ) as a regional scheme F9 - - - - none F11 23.8 18.5 5.3 - Although the IUA is in a surplus as a result of low upstream surpluses the IUA has nodal deficits. GW availability at H70B is 18.39Mm3. Deficit in H70B is 23.68Mm3. Cost 18.39@R5.0/m3. Rest is 5.29Mm3 at regional scheme costs. GW availability from H70G is 2.66 Mm3. Deficit in H70G is 0.09Mm3@R5.0/m3 From here on deficit reduces so no additional costing. Gouritz E8 - - - - none C6 - - - - none D7 25.3 11.2 - 14.1 The initial deficit occurs at J25A to J25E (14.0Mm3) . Only 6.6 Mm3 of this deficit can be supplied by GW. Rest (7.4Mm3) supplied by TMG. Then big jump to deficit of 25.3Mm3 at J40A. Incremental deficit is 11.3Mm3 with no deficit on Olifants. Groundwater at J40A is 4.64Mm3 and rest (6.66Mm3) supplied by TMG F13 - - - - none F12 - - - - none I18 - - - - none G14 - - - - none G15 2.8 2.8 - - none
gx3 K60G Piesang E 91.71 E 53.36 Gxi14 K60G Piesang B C 91.72 C 69.54 giv6 K60C Keurbooms B/C C 84.09 C 84.09 giv5 K60D Palmiet A 79.47 A 79.47 gx9 K60E Keurbooms B 81.51 B 81.51 giv4 K60F Bitou C 96.93 D 31.99 Gxi15 K60G Keurbooms A A/B 87.25 A/B 74.90 gx4 K70A Buffels B 91.11 C 43.82 Gxi16 K70A Matjies B B 91.12 B 67.46 gx5 K70A Sout B 91.12 B 91.12 Gxi17 K70A Sout(Oos) A A 91.11 A 91.11 gvii15 K70B Bloukrans B 77.49 B 77.49 Gxi18 K70B Bloukrans A A 91.84 A 91.84 Gxi19 K10A Blinde B B 96.16 B 98.00 Gxi20 K10A Tweekuilen D D 96.11 D 65.27 Gxi21 K10A Gericke D D 96.18 D 65.27 Gxi22 K10B Hartenbos C D 83.11 D 64.28 Gxi23 K70A Groot(Wes) B B 91.11 B 87.97
H16 Overberg West Coastal II High infrastructure costs to implement REC therefore water requirements for the ESBC used. Swart river node is in an unacceptable condition, and Onrus river node is improved from baseline but is still in a poor condition (i.e. C to below D Ecological Category). Buffels and Rooiels are in a good condition. To achieve this scenario into the future, the groundwater status increases compared to PES in four (of six) quaternary catchments. These four catchments include all those of the Overberg West Coastal, plus G40C of the Overberg West IUA. The increase in groundwater stress in these four catchments is moderate, with each catchment increasing its status by one equivalent category (i.e. increases from category I to II or II to III). One of the quaternary catchments impacted by a change in category (G40H) has been identified as having a high GWBF/EWR ratio, indicating groundwater contribution to baseflow has the potential to sustain the EWR. Abstraction would need to be carefully managed to ensure impacts on GWBF do not impact on the flow required for the associated EC. B5a Overberg West II The nodes at the bottom of the catchment should be maintained in a good condition (i.e. B to C Ecological Category). B5b Overberg West III Although there are regions within the Overberg West IUA that are of conservation importance, the surrounding land use in most cases has led to degraded systems. F10 Overberg East Renosterveld II Hartbees and Steenbok are in a poor condition. To achieve this scenario, the groundwater status increases compared to PES in one quaternary catchment (G40L, located in Overberg East Fynbos IUA). The increase in groundwater stress in this catchment is fairly significant, with the catchment increasing its use/ recharge ratio (‘stress’) from 19 to 88%. The quaternary catchment impacted by a change in category has not been identified as having a high GWBF/EWR ratio. H17 Overberg East Fynbos III High infrastructure costs to implement REC therefore water requirements for the ESBC used. Limited change from baseline condition. Conditions of river nodes are fair to poor. De Hoop Vlei and Klipdrifsfontein are maintained in a good condition.
F12 Duiwenhoks III This flow regime meets the REC of D for giii8 (Duiwenhoks River). The river node associated with Duiwenhoks wetland remains in an unacceptable condition. Despite flowing relatively naturally, a range of agricultural impacts such as clearing of riparian vegetation for cultivation and infilling in cultivated areas have meant that the rivers of the Duiwenhoks and Hessequa are in moderate to poor condition. Flow requirements are met for the REC of C/D at giii7 (Goukou River) with 80% of natural flows. Although there is an increase in total groundwater use for this scenario, the groundwater status does not change in any quaternary catchment. I18 Hessequa III The ecological condition of the Duiwenhoks and the Goukou estuaries are B and C, respectively, which is lower than the Recommended Ecological Condition of A and B, respectively. E8 Touws III Ysterdams, Donkies and upper Touws rivers at the upper reaches of this region and the upper Groot River remain in poorer condition. To achieve this scenario into the future, the groundwater status increases compared to PES in two quaternary catchments. These two catchments are J12B and J13C; located at the northwest (upstream) and southeast (downstream) extremities of the catchment respectively. The increase in groundwater stress in J12B is significant, with an increase in its use/ recharge ratio (‘stress’) from 2 to 100%, corresponding for a change in status category from I to III. The change at J13C is moderate. None of the quaternary catchments impacted by a change in category have been identified as having a high GWBF/EWR ratio. C6 Gamka-Buffels II Most river nodes are in a good condition. There is a minor increase in groundwater use in this scenario (compared to PES), however there is no change in groundwater status