# The Biological Assessment and Rehabilitation of the World's Rivers: An Overview
## 2 Biological Assessment of Rivers
### Africa
[PERSON] [49] identified signature traits to assess urban pollution in South Africa and a trait-based approach was useful for exploring the effects of fine sediments on riverine ecosystems [50; 51]. In West Africa, [PERSON] et al. [52] explored the pattern of distribution of traits and ecological preferences to urban and agricultural pollution. However, the greatest challenge is the paucity of life-history information on Afro-tropical macroinvertebrates and only one trait database has been compiled in the region [53]. The existing large-extent bioassessment programs in Africa have been triggered in response to specific events. The best-known example is the Onchocerciasis control program set up in response to the use of insecticides for controlling river blindness in West Africa. To evaluate the possible short- and long-term effects of insecticide application on non-target fauna, a biomonitoring program was set up between 1974 and 2003 covering 50,000 km of river and including 11 West African countries. The biomonitoring results demonstrated little effect on fish [54] and macroinvertebrate taxonomic and functional composition [55; 56]. Most dischargers into a receiving stream or river are required to undertake their bioassessment, up-and down-stream of the effluent discharge point. For this purpose, macroinvertebrate assemblages using the SASS5 protocol have been used, as well as other biological assemblages such as fish and riparian vegetation, depending on the nature of the water use. A diversity of stakeholders also implement bioassessments in Africa, and their programs include transboundary (regional), national, and local extents. The actors or stakeholders may be: (i) transboundary river commissions, international funding/multilateral institutions, (ii) national governments, (iii) community/citizens, and (iv) non-governmental organizations. For example, the Orange-Senqu River Commission (ORASECOM) is man dated to ensure equitable and sustainable management of water resources in the transboundary Orange-Senqu River basin, which covers 1,000,000 km\({}^{2}\). The river basin is located in four nations: South Africa (64.2% of its total coverage), Namibia, Botswana, and Lesotho. To date, ORASECOM has implemented two basin-wide bioassessment surveys using macroinvertebrates, fish, and riparian vegetation [57] by using common protocols developed in South Africa. Recently, the Nairobi Water Trust Fund in Kenya began supporting a pilot study to develop and use the USEPA's Biological Condition Gradient (BCG) approach [58] in the Upper Tana River watershed in Kenya, to assess water and landscape conditions to inform rehabilitation initiatives. In Lesotho, the Lesotho Highland Development Authority regularly monitors waters through macroinvertebrates, fish and riparian vegetation. Various community-based monitoring initiatives have also been in place for implementing bioassessment programs. In Gambia and Ghana bioassessment is currently being accomplished through community-based monitoring [59; 60]. In Southern Africa, community-based monitoring is widespread. A formal community-based assessment protocol called Mini-SASS has been developed using macroinvertebrates [61]. MiniSASS ([[http://www.minisass.org/en/](http://www.minisass.org/en/)]([http://www.minisass.org/en/](http://www.minisass.org/en/))) requires minimal training and citizens can collect and upload data into an online platform, using the MiniSASS app. Mini-SASS is also implemented in East Africa through a citizen science initiative called 'Adopt a River' in which students in primary and high schools assess river ecological conditions by measuring water physico-chemical variables and macroinvertebrates. In North Africa, despite the absence of established bioassessment programs, research and short-term assessments have been undertaken in rivers, namely in Morocco, Algeria and Tunisia. In Morocco, standardized methodology and well-known indices have been used such as: the IBD (Indice Biologique Diatomees) based on diatoms [62; 63] ([PERSON] et al.