Environmental Engineering Reference
In-Depth Information
4 MONITORING PROGRAMS AND REGULATORY PRACTICE
4.1
Institutions and technical background
Diffuse pollution monitoring and control should not be viewed as a task on its own, but
should be incorporated in the context and objectives of the water quality management of
the whole catchment basin. This section presents the status of the water quality
monitoring practice in the Chivero basin during the period 1995-2000. Two institutions
were responsible for this task - the city of Harare municipality and the Department of
Water Resources (DWR), Ministry of Land and Agriculture. Later on the DWR was
incorporated into the Zimbabwe National Water Authority (ZINWA). Both institutions
have their own water quality monitoring programs, with corresponding laboratory
facilities. The monitoring program of DWR has the support of a well equipped and
contemporary water quality laboratory, while the water quality laboratory of the
municipality is outdated and has limited resources in terms of equipment, space and
financial support.
The data storage and retrieval process at DWR was relatively well organized,
containing the monitoring data in the form of protocols. An upgrading of this system into
a computerized database was under construction. However, the city of Harare did not
have a well-organized data record system, with most of the measurements recorded as
part of the operational process of the treatment plants in topics. These findings show the
need to improve the data storage and record process, together with the reporting
procedures, in order to make use of the information obtained, and implement it during the
management process. If such a practice is not implemented, it could jeopardize the efforts
and costs involved during the process of samples collection and analysis.
4.2
Regulating water quality
The Zimbabwean regulations (WWEDR 2000) are discharge-oriented and are aiming at
enforcing in practice the “polluter pays” principle. They focus on the effluent discharges
to surface water, effluent and sludge disposal on land, and solid waste disposal sites.
Runoff quality is included in the different classifications only for specific cases as sludge,
effluent and solid waste disposal sites, and is treated as a point pollution source. Possible
pollution from agricultural or urban runoff is not envisaged, most probably because of the
difficulty to identify these types of sources of pollution and corresponding polluters. The
regulations provide for a permit classification based on effluent (runoff) characteristics,
sludge (effluent) application rates and the protection level of solid waste disposal sites.
They include a detailed list of water quality criteria, including blacklisted compounds,
which prescribe limit concentrations and qualifies the discharges based on environmental
hazard risks (ER) into four major groups: safe, low, medium and high hazard. A partial
consideration of the water quality orientated approach has been introduced by identifying
environmentally sensitive river catchments, where more stringent criteria are applied.
Considering the fact that a large number of the receiving water bodies in the country are
ephemeral, the safe prescribed limit of the different water quality criteria could be
