STATESTATE OFOF RIVERSRIVERS REPORTREPORT RIVERS OF THE GOURITZ WATER MANAGEMENT AREA 2007 RRIVEIVERR HHEALTEALTHH PPRROGOGRRAMMEAMME ii RIVERS OF THE GOURITZ WATER MANAGEMENT AREA 2007: SUMMARY The Gouritz Water Management Area (WMA) comprises the Goukou and Duiwenhoks, Gouritz and Garden Route rivers. Beaufort West The Gouritz River is the main river within the WMA. It originates in D the Great Karoo and enters the Indian Ocean at Gouritzmond. w y k 4HQVY[YPI\[HYPLZVM[OL.V\YP[a9P]LYHYL[OL.YVV[.HTRH a Leeu Gamka and Olifants rivers. The Goukou and Duiwenhoks rivers N1 are small rivers draining the Langeberg a Laingsburg k 4V\U[HPUZHUKÅV^V]LY[OLJVHZ[HSWSHPUZ B m u a f fe G west of Mossel Bay. The main rivers of the ls Garden Route, east of the Gouritz River, Touwsrivier Tou Olifants are the Hartenbos, Klein Brak, Groot Brak, ws Oudtshoorn Knysna, Bietou, Keurbooms, Groot and Calitzdorp G Uniondale root Bloukrans. Kammanassie George D u N2 Knysna i Land-use in the area consists largely of sheep and ostrich w G e Albertinia n G o farming in the arid Great Karoo, extensive irrigation of h o u o u r i Mossel Bay k t k z s Plettenberg o lucerne, grapes and deciduous fruit in the Little Karoo, and u Bay forestry, tourism and petrochemical industries in the coastal Stilbaai Gouritzmond belt. Indigenous forests, wetlands, lakes and estuaries of high conservation status are found in the wetter south eastern portion of the WMA. OVERALL STATE Generally, only the upper reaches of the coastal rivers and their tributaries in the WMA are still in a natural or good ecological state, while many of the lower reaches are in a good to fair state. Where the lower reaches of some of these rivers are degraded, it is as a result of the cumulative effect of increased development and water abstraction. The upper reaches of the Gouritz River in the Great Karoo are mostly in a good ecological state, while the middle and lower reaches are in a fair to poor ecological condition as a result of agricultural and urban development. Invasive alien WSHU[ZHUKÄZOOH]LOHKHTHQVYPTWHJ[VU[OLIPVKP]LYZP[`HUKLJVSVNPJHSM\UJ[PVUPUNVMYP]LYZPU[OL.V\YP[a>4( and their existence threatens the status of all endemic species. Portions of the area are protected through conservation PUP[PH[P]LZZ\JOHZ[OL.V\YP[a)PVKP]LYZP[`0UP[PH[P]LHUK[OL.HYKLU9V\[L0UP[PH[P]LHUK[OLZLPUJVUQ\UJ[PVU^P[O JVUZLY]H[PVUWYVQLJ[ZOH]LPTWYV]LK[OLJVUZLY]H[PVUZ[H[\ZVM[OLHYLH Gamkapoort Dam (Gamka River) IMPACTS -SV^ TVKPÄJH[PVU as a result of over-abstraction threatens the ecological functioning of many of the rivers. Extensive abstraction and many off-stream dams for agriculture, domestic use and new developments have had a J\T\SH[P]LULNH[P]LLMMLJ[VUÅV^,_[LUZP]LHSPLU]LNL[H[PVULUJYVHJOTLU[ adds to all these impacts on the rivers. This is particularly evident in summer, ^OLU ZVTL YP]LYZ JLHZL [V ÅV^;OLYL HYL H ML^ SHYNL PUZ[YLHT KHTZ [OH[ Stompdrift Dam (Olifants River) JVU[YPI\[L [V ÅV^ TVKPÄJH[PVU I` WYL]LU[PUN ZTHSSLY ÅVVKZ MYVT YLHJOPUN the estuaries. 4VKPÄLKÅV^ZHYLULNH[P]LS`PTWHJ[PUNVU[OLM\UJ[PVUPUNVM[OLYP]LYZHZ well as the overall ecological integrity. This, in turn, affects the ability of the systems to deliver certain goods and services (water supply, breakdown of pollutants). (NYPJ\S[\YL HSVUN [OL iii Olifants River (NYPJ\S[\YHSWYHJ[PJLZHUK\YIHUKL]LSVWTLU[PUÅVVKWSHPUZYPWHYPHUaVULZHUK wetlands have reduced water quality and habitat diversity in the middle to lower reaches of many rivers. These practices have reduced biodiversity and sustainable water resource use in the Gouritz WMA. They have also impacted on wetlands, reducing their ability to act HZZWVUNLZH[[LU\H[PUNÅVVKZHUKLUZ\YPUNWLYLUUPHSÅV^Z(ZHYLZ\S[YP]LYZYLTHPUKY` MVYSVUNLYWLYPVKZHUKÅVVKKHTHNLPZTVYLL_[LUZP]L(SPLU]LNL[H[PVULUJYVHJOTLU[ bulldozing, pastures and developments in riparian zones have further reduced their ability Beaufort West to buffer rivers from surrounding land-use impacts. This has reduced the ability of riparian D and wetland vegetation to remove nutrients and stabilise river banks. w y k a Leeu Gamka N1 The broad distribution of HSPLUPU]HZP]LWSHU[Zpose various threats >H[[SLPUMLZ[H[PVUVM[OL4VVYKR\PS9P]LY a Laingsburg k m to rivers in the Gouritz WMA. They reduce riparian habitat diversity, a G aquatic biodiversity, water availability and destabilize river banks. They also block rivers, resulting in lateral and mid-channel erosion, shade Touwsrivier Olifants Oudtshoorn ^H[LYJV\YZLZJHUWVPZVU[OL^H[LYHUKJYLH[LHÄYL[OYLH[ Calitzdorp G Uniondale root Kammanassie The Garden Route and Goukou/Duiwenhoks rivers and associated George wetlands are particularly threatened by the rapid spread of black wattle. N2 Knysna 6SLHUKLYPZWYL]HSLU[VUÅVVKWSHPUZHUKWLYLUUPHS^H[LYZ[YLHTZVM[OL Albertinia G o .V\YP[aJH[JOTLU[HUKPZL_[YLTLS`L_WLUZP]LHUKKPMÄJ\S[[VLYHKPJH[L u r i Mossel Bay t z Plettenberg Pepper trees and Spanish reed are other riverine alien plants in this Stilbaai Bay catchment. 0U[YVK\JLKHUK[YHUZSVJH[LKÄZOZ\JOHZIHZZJHYWIS\LNPSSZ\UÄZO TVZX\P[VÄZO[PSHWPHZTHSSTV\[O`LSSV^ÄZOHUK[YV\[WVZLHTHQVY[OYLH[[V PUKPNLUV\ZÄZOHUK[VYP]LYM\UJ[PVUPUN(SPLUÄZOHYL^PKLZWYLHK[OYV\NOV\[ [OLTPKKSLHUKSV^LYYLHJOLZVMTHU`YP]LYZVM[OL.V\YP[a>4((SPLUÄZO OH]LJH\ZLKSVJHSPZLKL_[PUJ[PVUZVMPUKPNLUV\ZÄZOWVW\SH[PVUZTHU`VM ^OPJOHYLLUKLTPJ[V[OLHYLH;OL`WYLKH[LVUPUKPNLUV\ZÄZOJVTWL[L MVYMVVKHUKHS[LY[OLPYOHIP[H[/LHS[O`U\TILYZVMPUKPNLUV\ZÄZOUV^ Banded tilapia survive only in refuge reaches of rivers that are beyond the reach of alien ÄZO Rivers of the Gouritz WMA generally have good water quality, except in /`HJPU[ONYV^[OK\L[VL\[YVWOPJH[PVUHUK the middle and lower reaches, where water quality is impaired (nutrient YLK\JLKÅV^ZPU[OL2SLPU)YHR9P]LY enrichment and salinisation) by KPMM\ZL WVSS\[PVU from intensive HNYPJ\S[\YHS HJ[P]P[PLZ 7VSS\[PVU ZV\YJLZ PUJS\KL PYYPNH[PVU YL[\YU ÅV^Z (fertilisers and insecticides), run-off from feedlots, roads, urban areas HUKPUMVYTHSZL[[SLTLU[ZHKQHJLU[[VYP]LYZHZ^LSSHZKPZJOHYNLZMYVT wastewater treatment works. Higher suspended solids occur during times VM ÅVVKZ 4PJYVIPHS JVU[HTPUH[PVU MYVT ^HZ[L^H[LY KPZJOHYNLZ VY [OL absence of adequate sanitation services pose a high risk to human health, particularly in those river reaches downstream of human settlements. Litter and solid waste dumping also reduce water quality and habitat integrity in some of the rivers. MANAGEMENT ACTIONS 0U]LZ[PNH[LHUKLUZ\YLLU]PYVUTLU[HSÅV^YLSLHZLZMYVTL_PZ[PUNPUZ[YLHTKHTZ^OLYLWVZZPISL +PZJV\YHNLNYV\UK^H[LYHIZ[YHJ[PVUMYVT[OLYPWHYPHUaVUL ,UJV\YHNLLMÄJPLU[^H[LY\ZL[OYV\NOV\[[OL>H[LY4HUHNLTLU[(YLH9LK\JL^H[LYSVZZMYVTJHUHSZHUKPTWYV]L PYYPNH[PVUTL[OVKZ ,UJV\YHNL LU]PYVUTLU[HSS`MYPLUKS` MHYTPUN WYHJ[PJLZ SPTP[ MHYTPUN HJ[P]P[PLZ PU YPWHYPHU aVULZ HUK THPU[HPU H I\MMLYHYLHTHSVUNYP]LYIHURZ *SLHYHSPLU]LNL[H[PVUMYVTYPWHYPHUI\MMLYHYLHZHUK[OLZ\YYV\UKPUNJH[JOTLU[9LOHIPSP[H[LJSLHYLKHYLHZ :[VJRKHTZ^P[OPUKPNLUV\ZÄZOYH[OLY[OHUHSPLUÄZO *VU[YVSSP[[LYHUKK\TWPUNVMZVSPK^HZ[LULHYYP]LYZ 0TWYV]LTVUP[VYPUNHUKTHUHNLTLU[VMZ[VYT^H[LYHUK^HZ[L^H[LYMYVTKL]LSVWLKHYLHZ iv PRESENT STATE: GOUKOU/DUIWENHOKS & GOURITZ RIVERS HUIS RIVER GAMKASKLOOF DWYKA RIVER EcoStatus: Fair EcoStatus: Good EcoStatus: Good F-G G F G G G N-G G G G G N G-G G G G G G Importance: M Sensitivity: M Importance: H Sensitivity: H Importance: H Sensitivity: M Desired State: Good Desired State: Natural Desired State: Good BUFFELS RIVER: LAINGSBURG EcoStatus: Poor F-P F P P P F Importance: L Sensitivity: L Desired State: Fair Merweville R29 D SEWEWEEKSPOORT w y EcoStatus: Good k a N-G G G G N G Importance: H Sensitivity: H N1 Desired State: Natural GROOT RIVER: VAN ZYLS DAM EcoStatus: Fair F-F F F F P F B u f Laingsburg fe Importance: L Sensitivity L ls Desired State: Fair Touwsrivier GROOT RIVER: R62 EcoStatus: Fair Tou ws G-F G G F F G Ladismith G r Calitzdorp o Importance: M Sensitivity: M o t Desired State: Good G root TOUWS RIVER: R62 R62 EcoStatus: Good Van Wyksdorp G-G G G G G G Importance: M Sensitivity: M Desired State: Good Heidelberg GROOT RIVER: VAN WYKSDORP D Riversdale u i EcoStatus: Fair w e F-G G F F F G n h Albertinia N2 o G k o s u k Importance: M Sensitivity: M o u Desired State: Good DUIWENHOKS: DORINGKLOOF Stilbaai EcoStatus: Fair G-F F F G F G Importance: VH Sensitivity: H Desired State: Good DUIWENHOKS: HEIDELBERG EcoStatus: Poor GOUKOU: KLIPFONTEIN F-P P F F F P EcoStatus: Fair F-F F F P F P Importance: H Sensitivity: M Desired State: Fair Importance: H Sensitivity: M Desired State: Fair VET RIVER: KOINTEPOORT DAM EcoStatus: Good GOUKOU: RIVERSDAL EcoStatus: Fair N-G G G N G N DUIWENHOKS: VERMAAKLIKHEID F-P P P F P P EcoStatus: Fair VET RIVER: NOVO Importance: VH Sensitivity: VH G-F F F F F G EcoStatus: Fair Desired State: Natural G-F F P G G G Importance: H Sensitivity: M Desired State: Fair Importance: H Sensitivity: M Desired State: Good Importance: VH Sensitivity: VH Desired State: Good v NELS RIVER KRUIS RIVER GROOT RIVER: PARADYSKLOOF EcoStatus: Fair EcoStatus: Fair EcoStatus: Good G-F G P G G G G-F F P G G G G-G G F G G G GAMKA RIVER: LEEU GAMKA Importance: H Sensitivity: H EcoStatus: Fair Importance: M Sensitivity: M Importance: H Sensitivity: H Desired State: Good G-F F P G F G Desired State: Good Desired State: Good GOURITZ RIVER: VAALHOEK LOWER OLIFANTS RIVER Importance: M Sensitivity: M EcoStatus: Good EcoStatus: Poor Desired State: Good G-G N G G P G P-P P P F P F Importance: L Sensitivity: L Importance: L Sensitivity: L Desired State: Good Desired State: Fair GROBBELAARS RIVER EcoStatus: Fair F-G F P G F G Beaufort West s r e Importance: H Sensitivity: M o m Desired State: Good e k u e e o e L GROOT RIVER: MEIRINGSPOORT