The presence and levels of major nutrients in the water from Vondo and
Albasini Dams and their water treatment plants have been assessed to
determine trophic status of the dams and impacts on aquatic ecosystems
and drinking water. Water quality parameters particularly phosphates
and nitrates are critical in assessing the trophic status. Water
quality parameters linked to eutrophication and agrochemicals were
analyzed. Phosphate was undetectable in both dams. The nitrate levels
in Albasini and Vondo Dams which were from 1.16 to 6.65 mg/L and 0.46
to 4.19 mg/L, respectively, were within and above the South African
guideline for aquatic ecosystems of 2 mg/L. The raw water pH for Vondo
and Albasini Dams were from 6.20 to 7.46 and 6.35 to 8.70,
respectively, and were mostly within acceptable guidelines for aquatic
ecosystems. The water transparency for Vondo and Albasini Dams were
from 0.5 to 4.2 m and 0.4 to 0.9 m, respectively. The levels of all
other water quality parameters investigated in both dams and their WTPs
mostly indicate low, rarely high and no water quality problems in
aquatic ecosystems and drinking water. The low levels of total
suspended solids and water transparency, the pH range, low to high
electrical conductivity, low to acceptable dissolved oxygen levels,
acceptable to high biological oxygen demand and nitrate levels for both
dams indicate oligotrophic to eutrophic states. Though oligotrophic
state dominates, the mixture of trophic states has been attributed to
increase in urbanization and intensive agriculture
