Table 1 Sampling points in the three study areas

Hex River Valley

E*

River point high up the valley, towards the top of the production area

F

River point in the middle of the river's course through the valley, at densely agricultural area

G

River point at lowest end of the valley, after confluence with a fresh river from pristine area

L*

River point between F and G

M*

River point – between E and F, before discharge of Bdr

Ar

Farm reservoir near vineyards containing spring and mountain water

Br

Farm reservoir containing mountain water near vineyard

Cdr

Open surface drain (1 m); drains superficial vineyard run-off

Bdr

Closed surface drain (1 m); drains vineyard run-off from farm and from neighbouring farms.

Dd

Open farm dam receives water from the Hex River

H

Shallow well (5 m deep), containing groundwater used for domestic consumption

J

Tap at Irrigation Board offices: representing potable water supply to the valley from distant mountain dam close to Ceres

K*

Point on another river near F

Grabouw / Vyeboom

G1d

Dam receives irrigation drainage, flows into Palmiet river

G2d

Farm dam, water pumped from Palmiet.

G3

River point (Palmiet) in midst of intensive agriculture

G4

River point lower in the course of the Palmiet

G5d

Dam receiving water from Palmiet river, other dams and irrigation run-off; purified for domestic use.

G6b

Well (in Vyeboom) used by farmers for domestic use, 30 m in depth

G7*

A stream flowing from agricultural area in Vyeboom into the Theewaterskloof Dam (supplies just over 50% of Cape Town's drinking water). The stream is part of the dam when the dam is full.

G8t

Tap water using output of G5d

G9

River point on Palmiet after joining Krom

Piketberg

P1b

Well (depth = 100 m) in intensive farming area; used for domestic water supply

P2d

Dam receiving well and surface water but near the top of the mountain

P3b

Well (depth = 70 m) in intensive farming area; used for domestic water supply

P4r

Stream running down the mountain from P2d through Moravian Mission and into the Berg River. Used for domestic consumption.

P5r

Site on Berg River mid-way further on from P4r

P6r

Site on Berg River at pumping station providing municipal water

P7b

Well (depth = 100 m) on wheat farm on the plain below the mountain.

P8r

Tap at water purification scheme at Wittewaters (Berg River)