Aquatic Biomonitoring – Case Study By Sean Altern – Consultant: Biodiversity Conservation Services
How do you know if a development is, or is not, causing harm to a river or watercourse? SASS5 Aquatic Biomonitoring is a service offered by NCC Environmental Services (NCC) that produces verified results in order to ensure sustainable development and the protection of our environment.
Aquatic Biomonitoring and SASS5
SASS5 works on the following principle: Biodiversity equates to ecosystem health and change in biodiversity corresponds to a cause. If a stream contains a fish it must be a healthy stream. Otherwise there would be no fish right? If it contains fish and a crab, this must mean it is even better. What if it contains fish, a crab, beetles and bugs? This must be really good then! But what if it has none of these? Or only has them in certain sections…
The analyses of these findings and questions are in essence the principle behind SASS5, the South African Scoring System version 5 for monitoring of rivers and streams.
How Aquatic Biomonitoring works
The SASS5 system is an empirical, carefully designed and refined methodology used to provide a scientific and credible assessment of the status or health of a river by means of examining the aquatic macroinvertebrates or, in simple terms, ‘water insects’, found in a particular reach of river.
Whilst limited in some regards it is, when applied correctly and routinely with careful consideration for external environmental factors, a great rapid assessment tool for determining and monitoring the health status of sections of rivers.
At each site along a river the SASS5 protocol is followed and the specified sampling techniques used to collect macroinvertebrates. These small creatures have, through years of research and systematic consideration, been assigned various scores or points based on sensitivities and habitat requirements.
Insects with greater sensitivities to pollution or disturbance are likely to score higher. The more varied the creatures found in a particular section of stream, the greater the overall SASS5 score will be when the results are added up. These scores are then assessed in accordance with external factors such as the season and geographical location which has bearing on aquatic species in the same way it has bearing on terrestrial species i.e: You won’t find a Gorilla in Cape Town, but you will find a baboon. Variances in natural distributions are common throughout regions and within the differing reaches of streams, all factors that are included in the interpretation of scores.
Aquatic Biomonitoring can protect the environment as well as developers.
As the SASS5 methodology is a set protocol and all practitioners are accredited, this means that all assessments are being conducted in an identical manner. As a result, if changes in scores occur over time for a particular stretch of river, and tests were conducted in the same season, we can then conclude that the health of the river has changed for some reason.
SASS5 does not tell us why changes have occurred (these could be due to natural occurrences such as floods, recent heavy rains or even fires) nor does it pinpoint the exact location or source of a problem. However, by conducting interval assessments the general source area of the problem(s) can be isolated. For instance if the SASS5 score is high further upstream yet 100m downstream, and in a similar stretch of river, it is much lower it is then likely that the source cause of the problem is within that 100m stretch. If there is a factory or new development within the 100m stretch then there is a probable cause identified for further investigation.
SASS5 routine monitoring can be used both up and downstream of developments during pre-construction (for vital baseline results), during construction and in the operational phases as an aquatic biomonitoring programme to ascertain if and when the watercourses are being negatively impacted upon. The results allow the general health of the river to be continually monitored, alerts to be issued and remediation or further safeguarding measures implemented as a result. This monitoring thereby protects the environment as well as developers. If a SASS5 score changes downstream as well as upstream from of a new development the source of this change cannot be attributed solely to the development as it would not be able to influence up current results.
It is thus vital that all developments that can or are having an impact on rivers or watercourses are monitored via SASS5 aquatic biomonitoring.
Correlation does not always equate to causation and this applies to SASS5 score analyses. Though changes in results can occur there are often multiple factors involved and which are all recorded and scrutinised in the reports produced by NCC for their clients. Results are seen as indication of change and an alert to investigate the possible cause.
The key aspects for the implementation of a SASS5 biomonitoring programme is “consistency” and “scope of monitoring” along with careful analysis of associated influences. These elements all help to paint an overall picture of the state of the river and probable causes of change.
Developments affecting a watercourse should be conducting SASS5 aquatic biomonitoring
NCC Environmental Services SASS5 practitioners are accredited by the Department of Water Affairs and Sanitation to perform SASS5 assessments on all projects. This information can also be used to build up a record of the state of the rivers throughout South Africa by feeding the data into the authorised online National Aquatic Ecosystem Health Monitoring Programme.
Every development that is near, or which could affect a watercourse, should be conducting SASS5 aquatic biomonitoring to ensure that the operations are not effecting downstream environments and livelihoods. This is often a stipulated requirement on projects and helps to safeguard our precious natural water resources.