Globally, rivers are the most vulnerable aquatic systems due to increased exposure to intertwined stressors (Mamun and An, 2020). These stressors, particularly human settlements and other anthropogenic activities, have an immense impact on river systems’ health. Social stimulation models have been used to assess the health status of several river systems, including identifying the Drivers, Pressure, State, Impact, and Response (DPSIR). However, the DPSIR framework, which elaborates the cause–effect relationships between interacting components of social, economic, and environmental systems, had barely been used in East Africa before. However, several drivers affecting rivers in Uganda and Kenya have been reported by Andreas Melcher (Personal communication, 22nd February 2023, during an online training on Community-Based Water Quality Monitoring in River Health). Agriculture, industry, and urban development have been identified as the key drivers, with pollution and physical alteration of channel characteristics being the main pressures. However, DIPSIR requires the availability of water quality data and information, indicating the necessity of a structured health monitoring system for the river basins. This has been a big challenge for many rivers, especially in East Africa, posing a gap toward the development of science-based management regulations and policies (Kagalou et al., 2012; Sendzimir and Schmutz, 2018; Georgiou et al., 2024). In addition, factors such as the timing and duration of the sampling period may cause differences in the estimates of targeted organisms and benthic biodiversity reported for some West African streams (Kaboré et al., 2016).

Furthermore, the development of environmental monitoring tools strongly relies on several principles: technical co-evolution of data processing techniques, the use of scientific principles in the design of monitoring systems at the local, regional, and global scales, and the use of data from humankind risk assessment and the environment (Feld et al., 2011; Dahm et al., 2013). To put in place a monitoring system, information systems are key for effective long-term management strategies of water systems, of which many are facing complex socioecological challenges (Naigaga et al., 2011). Therefore, information leading to an understanding of the effects of some of the key environmental stressors (land use change, urbanization, and industrialization) on the status of river resources is essential for formulating effective basin management plans (Urbanič et al., 2020) for wise use. This infers that there is a need for a concerted effort to enhance river systems’ health monitoring due to their close proximity to the people and their livelihoods, hence more exposed to human-impacted stressors. Exploring other options for data acquisition to gather more information on the ecological integrity of rivers is crucial. The option of citizen science through community-based action for empowering citizens to monitor the status of their immediate rivers, identify issues and causes, and lobby for action from relevant water authorities cannot be ignored in the 21st century, where the world is facing major environmental challenges such as climate change and its extreme hydrological impacts, particularly to rivers.

Citizen science, also sometimes referred to as community science, has drawn a lot of attention since the mid-1990s. There are several definitions of citizen science in literature (Hecker et al., 2019) derived from either policy or practice impacts. Haklay et al. (2021) demonstrated the complexities and challenges of defining citizen science based on different contexts and objectives of those defining it: policymakers, funding agencies, scientific communities, and practitioners. However, when adopting citizen science initiatives, a common understanding among the relevant stakeholders would be enough to identify the influencing factors and preconditions to develop citizen science practices in the required context. This study adopts a broad definition of citizen science to refer to the active engagement of the general public (of varying education levels) to produce new knowledge for science and society in collaboration with scientists. The general public is then viewed as citizen scientists whose motivation is the desire for awareness to increase their scientific literacy, initiate policy and decisions, or fill gaps in societal academia-led monitoring of ecosystem health (Whitelaw et al., 2003; Conrad and Hilchey, 2011). Their motivation may be influenced by age, level of education, gender, and socioeconomic status. Community-based monitoring is a concept of citizen science defined as “a process where concerned citizens, government agencies, industry, academia, community groups, and local institutions collaborate to monitor, track and respond to issues of common community (environmental) concern” (Whitelaw et al., 2003; Conrad and Hilchey, 2011) and/or co-management of natural resources and catchments, where stakeholders are all involved (Keough and Blahna, 2006).

Citizen scientists play a fundamental role in the conservation of river ecosystems. The Kenyan Water Act, 2002, section 15 (3e), led to the formation of Water Resource Users Associations (WRUAs) in Kenya, similar to Water Users Associations (WUAs) in Tanzania (Allouche, 2016; Richards, 2019). Water associations are registered and voluntary community groups comprising men and women of varying ages and education levels living within river catchments. It recognizes the role of communities in the stewardship and management of water resources, which was included in the Citizen Index of Ecological Integrity (CIEI) (Aura et al., 2021). Their role is to monitor water quality, resolve water conflicts arising from water use, share information and ideas about rivers, and protect and conserve them. In most cases, community-based water quality monitoring is mainly through visual observations of water, which does not reveal the ecological status. Despite East African countries transitioning initiatives to use biomonitoring for water quality, the development of citizen science is still at a rudimentary budding state (Requier et al., 2020). Therefore, this study gives novel insights into possible biomonitoring tools, such as indices and models, and identifies suitable indicators that are easy to adopt, affordable, and reliable for assessing river health. However, for successful citizen science monitoring, the volunteers need awareness of the tools available and those that they can easily use through training and retooling.

Citizen science creates awareness of the necessity of continuous monitoring of rivers and the need for data quality assurance in the communities. Bioassessment has been identified as one of the best strategies to monitor aquatic systems’ health and response to disturbance and environmental characteristics shifts. Therefore, the need for bioassessment studies of these systems has led to the development and adoption of various biomonitoring tools (Table 1). In recent times, initiatives for the development of different bioassessment tools for African river systems based on different responses of organisms to environmental variations are on the increase. Bioassessment tools are mostly preferred because they are sensitive, highly robust, cost-effective, and easy to interpret (Dalu et al., 2016). However, no single tool can be used across all the river systems because of their diverse and sometimes dynamic characteristics, especially in tropical systems.

Rapid Bioassessment Protocols (RBPs) are some of the tools that have been proven to be reliable and quick in evaluating the water quality of riverine ecosystems (Lowe et al., 2013). South African Scoring System (SASS) was first developed in Africa using riverine macroinvertebrates to evaluate the state of South African rivers (Dickens and Graham, 2002) and in Zimbabwe (Mwedzi et al., 2016). SASS has been further modified, standardized, and adopted by other countries, such as the Zambia Invertebrates Scoring System (ZMSS), Okavango Assessment System (OKAS) in Botswana, and Namibia Scoring System (NASS) (Lowe et al., 2013). SASS has also been successfully adopted in other sub-Saharan countries, including Ethiopia, where a laboratory-based macroinvertebrate biotic system (ETHbios) was developed (Aschalew and Moog, 2015). In Nigeria, for instance, the Niger Delta Urban Multimetric Index (MINDU) has been developed and applied for evaluating the water quality of urban rivers (Edegbene et al., 2022) in addition to various biometric indices, including Hilsenhoff’s Biotic Index previously adopted for water quality monitoring in the country (Ogbeibu et al., 2013).

In East Africa, SASS has been applied with modifications successfully in Uganda and Tanzania, for example, Rwenzori Score (RS) and Tanzania River Scoring System (TARISS), respectively. Furthermore, TARISS has been applied successfully in the Rwanda and Uganda river systems (Dusabe et al., 2019; Tumusiime et al., 2019). In Kenya, SASS version 5 has been used in many rivers, including the Mara River (Oigara and Masese, 2017) and the Mount Kenya Rivers (M’Erimba et al., 2014). However, one of the limitations of RBPs is the adoption in non-wadeable rivers more than 20 m wide, which tend to adjust their sensitivity to different pollution types, hence affecting the interpretation of outputs due to high community structure variation coupled with patchy distribution (Dallas et al., 2018).

Other indices used in bioassessment tools in East Africa include multimetric indices such as the Benthic Index of Biological Integrity (B-IBI), which has been used for assessing macroinvertebrates in Tanzania (Elias et al., 2014) and Kenyan rivers (Masese et al., 2009). Elsewhere, bioindicators have been integrated into monitoring aquatic ecosystems. Although a wide spectrum of aquatic organisms can be used as bioindicators, regional indices extensively focus on macroinvertebrates, diatoms, ciliates, and fungi. However, they are hardly identified to the lowest taxonomic level, resulting in some uncertainty and sometimes inaccuracy of the system health categorization. Therefore, this study provides the framework for future studies on the use of biomonitoring tools to support decision-making for better management and conservation of rivers, particularly in East Africa, and integrating the approach of including citizen science in ecosystem health monitoring (Chandler et al., 2017; Aura et al., 2021).

A thorough literature review was conducted to identify the advancements of biomonitoring and to establish a community-based bioassessment protocol using selected bioindicators for East African rivers. This study adopted a comprehensive literature search using various search engines, including Google Scholar, Science Direct, and Web of Science. The search was narrowed down to the use of biomonitoring, bioindicators, community-based collaboration, environmental changes, citizen science, river ecosystems management, and water quality as keywords. The inclusion criteria for peer-reviewed publications were based on relevance to the topic and publications between 2000 and 2023, although some aspects required older publications (history and evolution of biomonitoring). Publications that were not available in English were excluded. The study further employed in-depth review and analysis of information from different peer-research reports and reviewed publications. Published research articles, reports, theses, and conference proceedings were reviewed.

Biomonitoring began 350 years Before Christ (BC) when Aristotle (A Greek philosopher) found “black mud” and “red tubes” growing out of “white slime” in brooks contaminated with sewage (Moog et al., 2018). Aristotle concluded the brooks had low oxygen, evidenced by black decaying mud (caused by the sewage), a community of Beggiatoa sulfur bacteria (white slime), oligochaete sludge worms, and chironomids (red tubes). After 1800 years, Friedrich Kolenati discovered that caddis larvae were absent in a stream that had factories on the upper section. The concept of biological indicators of pollution, generally called the saprobic system, was developed around 1900 by two German scientists, namely R. Kolkwitz and M. Marsson (Persoone and De Pauw, 1979). They used benthic algae and invertebrates as bioindicators. They called organisms in clean water `Kathrobien` and those in polluted water as `Saprobien.`

After World War 11, Liebmann introduced visualization of the river’s ecological status in the saprobic system using color bands. Politicians, decision-makers, and water managers became interested in the new saprobic system. Later, in Pantle and Buck (1955) developed the saprobic system to quantify pollution (Moog et al., 2018). This index was easy for the users to interpret. It ranged from 1 (very good quality) to 4 (extremely poor quality). Around the same time, a biotic index was developed in the United States (Beck, 1954). The index was developed to quantify the extent of stream pollution and its effects on stream biota. In 1961, the concept of saprobic valences was introduced in saprobic system by Zelinka (1961). This concept reflected a 100% occurrence of taxon among four water quality classes. In 1973, Sládecek wrote a book titled “System of Water Quality from the Biological Point of View.” This book was used in Central and Eastern Europe until the saprobic system was modified again by the European Water Framework Directive 2000/60/EC (WFD) to include more water quality elements, type-specific reference conditions, and protocol to classify ecological status (Moog et al., 2018).

Several methods have been developed since the concept of biomonitoring began. From the mid to late 1980s, Rapid Bioassessment Protocols (RBPs) for macroinvertebrates, fish, and periphyton were developed. The macroinvertebrate protocol was the most commonly adopted and used due to its sedentary nature and sensitivity to a wide range of anthropogenic pressures and stressors (Wen et al., 2017; Moog et al., 2018; Ruaro et al., 2020). In South Africa, the first biotic index was developed in 1972, but it required intense labor (Chutter, 1998). The index was based on subjective scoring considering the presumed sensitivity or resistance of each taxon to impairment. South Africa Scoring System (SASS) was developed later (Dickens and Graham, 2002). Since then, other countries in Africa have developed their own biotic indices mainly by modifying SASS (Dallas, 2021). To date, there are several initiatives by countries in Africa targeting the development or modifying existing indices suitable for their river monitoring programs.

Most rivers are subjected to multiple stressors, and therefore, determination of the present ecological status by the use of bioindicators is of vital importance in guiding management and conservation decisions (Masese et al., 2023). Consequently, the development and application of bioassessment and biomonitoring techniques is an essential component of Integrated Water Resource Management (Masese et al., 2021). Integrated Water Resources Management (IWRM), as defined by the Global Water Partnership (GWP), is the process that promotes the coordinated development and management of water, land, and related resources to maximize economic and social welfare in an equitable manner without compromising the sustainability of vital ecosystems (Agarwal et al., 2000). Biomonitoring serves as a vital component of IWRM due to its provision of real-time data on aquatic ecosystem health, early detection of pollution, cost-effectiveness, and understanding of complex interactions between environmental factors and biological communities, and thus guides decision-making processes in water management (Pandey et al., 2018; Sumudumali and Jayawardana, 2021).

Maintaining or restoring aquatic ecosystem integrity guarantees that ecosystem services remain preserved, as well as maintaining the biological, physical, and chemical components of ecological integrity (Barbour et al., 2000). Most water laws and regulations, such as the Clean Water Act (CWA) of the United States of America (USA) and the Water Framework Directive (WFD) of the European Union (EU), acknowledge the interdependence of these three components and emphasize the need to combine evaluations to assess ecosystem health (Barbour and Paul, 2010). The EU’s Water Framework Directive (WFD) prioritizes the use of biotic factors, including fish, macroinvertebrates, and aquatic plants, for assessing freshwater quality in streams (Gritzalis, 2006). Many countries with aquatic ecosystem assessment programs recognize the value of biomonitoring as a tool for IWRM and have adopted a strategy that uses biological indicators as barometers for ecological conditions and trends (Jungwirth et al., 2012), as well as a scientific foundation for decision-making on aquatic resource management (Moog et al., 2018).

The CWA, USA, and WFD, EU, are the initial IWRM frameworks directly implementing extensive biomonitoring and bioassessment systems. Similar legislations do exist in other countries, for instance, South Korea (National Stream Health Monitoring Act), Australia (Sustainable Rivers Audit), New Zealand (Resource Management Act), South Africa (National Water Act), and Canada (Canada Water Act) (Masese et al., 2013). Within East Africa, Kenya’s current legislative framework for IWRM includes the Environmental Management and Coordination (Water Quality) Regulations of 2006 (Government of Kenya, 2006), which aims at the protection of water sources such as lakes, rivers, streams, springs, and wells. The Water Act of 2002 (Government of Kenya, 2002), which focuses on the management of water resources, regulates water supply and sewerage services. The Environmental Management and Coordination Act (EMCA) of 1999 (EMCA, 1999), which focuses on protecting rivers, lakes, and wetlands, mandates the National Environmental Management Authority (NEMA) regulatory role in the conservation of biological diversity. In Uganda, the Water Act of 1997, the National Water Policy of 1999, and the Uganda Law Reform Commission (2000) have been designed to “provide for use, protection and management of water resources and supply; to provide and facilitate water supply and sewerage undertakings, and manage water resources in a sustainable manner for the benefit of the people of Uganda” (Zizinga et al., 2015). Tanzania implemented a River Basin Management Approach for water resource management in the 1980s, where the nation was sub-divided into nine management regions after the amendment of the Principal Act No. 42 of 1974 (Sokile et al., 2005). The country’s first National Water Policy was adopted in 1991 as a supplement to reforms in the water sector. Currently, the Water Resources Management Act of 2022 (Government of Tanzania, 2009) provides the institutional and legal framework for the development and sustainable management of water resources to generate principles for water resources management. Although the above EA legislative frameworks do not explicitly mention biomonitoring as one of the tools to be used, they do acknowledge the importance of habitat resource quality management, which includes the physical, chemical, and biological characteristics of the water systems. Although bioassessment and biomonitoring are still in their early stages in many countries, especially in Africa, they are expanding fast as a scientific foundation for decision-making on aquatic resource management. A good example is the adoption of TARISS in the national water monitoring program in Tanzania.

Bioindicators are a group of organisms whose quantity, existence, and nature project the quality of ecological conditions (Parmar et al., 2016; Moog et al., 2018). They are fundamental mirrors of ecological impacts and are, hence, instrumental in the development of strategies for the conservation and management of ecosystems. They further noted that bioindicators have the ability to assimilate both long- and short-term fluxes in an array of ecological variables.

Many indicators, including physical, chemical, and biological indicators (bioindicators), have been used to evaluate living or non-living elements in the environment and to monitor environmental change (Bowler and Bohning-Gaese, 2017; Gustavsson et al., 2017; Areco et al., 2021; Dias et al., 2021). However, water quality approaches are useful in identifying different sources of contaminants and checking compliance with set limits. However, these methods are less effective in comparing sites impacted by different water quality (Debels et al., 2005). Furthermore, Abdelkarim (2020) reported that bioindicator species can respond to environmental changes and biological effects in a comprehensive and dynamic way, providing a basis for accurate assessment of ecological changes. Therefore, biological monitoring using the response of bioindicators provides a much easier way to measure ecological integrity due to environmental change (Dolédec and Statzner, 2010).

In the last few decades, several biological metrics and indices have been developed to assess the ecological status of riverine ecosystems using bioindicators (Table 1). Most metrics and indices have been developed based on five biological quality elements: macroinvertebrates, fishes, phytoplanktons, benthic diatoms, and macrophytes (Birk et al., 2012). These key elements are efficient in monitoring anthropogenic impairment on the lotic ecosystem because they respond to different stressors affecting water quality (Gabriel et al., 2017). Furthermore, there has been increasing use of other bioindicators in river monitoring, including fungi (Samson et al., 2020), ciliates (Kulas et al., 2021), and bacteria (Chen et al., 2022). However, the type and characteristics of the river system being investigated and the pollution source determine the choice of the key bioindicator element to be chosen for monitoring. Furthermore, other environmental factors such as temperature, light transmission, and suspended solids affect the distribution of bioindicators in ecosystems (Khatri and Tyagi, 2015) and must be taken into consideration when choosing bioindicators. Some bioindicators for assessing the ecological quality of African rivers are discussed below, and key factors are summarized in Table 2.

Globally, water policy reforms have been enacted in many countries. East African countries, including Kenya, instituted major reforms in the water sector, enabling the enactment of The Water Act (2002), which resulted in the establishment of various WRUAs. Thereafter, the Integrated Water Resource Management (IWRM) framework advocates for water resource management from the highest to the lowest level of governance (Baldwin et al., 2015). Furthermore, the enactment of the Water Act of 2002, the Kenyan Constitution of 2010, and the revised The Water Act, 2016 acknowledges the role of WRUAs in resource management at the grass root level (The Water Act, 2016). In Tanzania, the Water Management Resource Act of 2009 permits WUA operations on the basis of fulfilling IWRM pillars. WRUAs were established in all catchment areas within Kenya (The Water Act, 2016) and Tanzania (Richards, 2019). However, Kenya WRA’s (2015) performance report indicated that only 56% of anticipated WRUAs had established their operational plans. This calls for relevant stakeholders to support Water Resource User’s activities through funding and technical advice.

Over time, WRUAs have transitioned toward the realization of the association’s status through registration under the Societies Act, with the support of World Wildlife Funds (WWF), for example, Mara WRUAs covering the entire Mara basin. However, both WRUAs and WUAs have faced a myriad of interlinked challenges, including the inability to bring members together and diverse ecological characteristics between upper and lower catchments, which have made it difficult to achieve their set objectives. In Kenya, this resulted in creating partnerships and collaboration with different allies, including WWF and Water Resource Authority (WRA), which has led to the recognition of many WRUAs along major tributaries: transboundary River Mara in Kenya (upstream) and Tanzania (downstream). In Tanzania, WUAs have collaborated with the Tanzania Forest Service Agency (TFSA), the Africa Wildlife Foundation (AWF), and NGOs toward mitigation and restoration strategies for water resources (Ngonyani and Mourad, 2019). In Kenya, the amendment of The Water Act (2002) provides a clear guideline on coverage area, resulting in the disintegration of six existing WRUAs into 25 smaller units to conform to the water quality regulation (Richards, 2018). Furthermore, the WWF led the communities in the implementation of activities that generated alternative livelihood and better land use practices toward better management of water resources.

In Uganda, the Water Act (1999), which is the principal law regulating the water sector, adopted decentralization of decision-making, responsibilities, and implementation of the function, leading to the adoption of demand-driven approaches in the water sector (Naiga and Penker, 2014). Local Government Act (1997) empowers local government to provide safe water using mobilized and grant resources GoU, (1999). Furthermore, the Water User Committee (WUC) is the executive organ of the water user group responsible for maintaining, operating, and managing water resources (Water Aid, 2013). However, WUC faces a number of challenges, including a lack of participation from the community, inadequate resources, and poor management (Terry et al., 2015). As a result, the National Association of Professional Environmentalists (NAPEs) conducted a series of workshops to evaluate, monitor, and improve WUC functions. User-friendly handbooks were developed to permit community users to learn about their rights and responsibilities toward the proper functioning of WUCs (Terry et al., 2015). Thus, more requisite institutional structures and collaboration with other various agencies are critical for the effective management and conservation of water resources by communities in East Africa; a key focus of this study to advise on easier ways to strengthen impactful community water quality monitoring.

A variety of factors influence the selection of an ecosystem assessment and monitoring program, including research costs, human resources, and data requirements (Norris and Hawkins, 2000). Biomonitoring of aquatic ecosystems in African systems lags behind other regions due to a lack of financial commitment, technical capacity, and biomonitoring guides. Despite these challenges, there has been a development of several regional or country-specific indices (e.g., Dickens and Graham, 2002; Aschalew and Moog, 2015; Kaaya et al., 2015). The majority of these indices and programs are based on physical and chemical parameters and biological communities (Aura et al., 2020), which have been adopted especially in monitoring East African rivers by scientists. Nevertheless, these programs are limited in the quantity of data collected across large spatial and temporal scales (Achieng et al., 2020). Due to the limitations of these indices, researchers have come up with new approaches to river health monitoring, and citizen science has emerged as one of the methods (Chandler et al., 2017). At the same time, citizen science offers numerous advantages; in most cases, it is highly content-specific, which could come with limitations, especially on the legibility and reliability of the data collected. Therefore, citizen science should not replace traditional biomonitoring approaches to rivers but complement the scientific monitoring systems.

Citizen science involves community members voluntarily participating in the provision of information or data collection in accordance with a protocol provided, developed, and validated by experts (Aura et al., 2020). This is consistent with co-management approaches, which provide stakeholders with a platform for long-term management practices of aquatic resources (Obiero et al., 2015). The citizen science monitoring approach has greatly enhanced the inclusion of citizens in natural resources stewardship monitoring (Mochizuki and Yarime, 2016). Nevertheless, the development of citizen science as a natural resource assessment and monitoring approach is quite limited in Africa, and in most cases, it is in its nascent state (Requier et al., 2020). Citizen science has the potential to directly connect scientists to the public and share the significance of their research (Crocker et al., 2019), enhancing public participation in scientific research.

There is a paucity of information on the application of citizen science in environmental monitoring, especially in many African countries (Requier et al., 2020). Nevertheless, Aura et al. (2020) tried to address the need for its application where they developed a “Citizen Index of Ecological Integrity (CIEI)” for assessing and monitoring the ecological status of African riverine ecosystems in Lake Victoria. Furthermore, Njue et al. (2021) used a contributory citizen science approach to determine the spatiotemporal turbidity and suspended sediment dynamics in the Sondu-Miriu river basin, western Kenya. This implies that citizen science could be strategically the voice of the future to produce pertinent management-oriented knowledge and create collaborations among the stakeholders to fill the data and information gaps at a reasonable cost.

Citizen science in many African countries is a new phenomenon and is worse off in East Africa despite having been well-established in other countries. The following review discusses successful citizen monitoring initiatives both in Africa and other countries. One of the best examples of citizen science monitoring in Africa is Burkina Faso (West Africa), where fishermen were involved in fish sampling under the Sustainable Management of Water and Fish Resources (SUSFISH) project. The goal of the project was to strengthen capacities for science, policy, and practice and establish a basis for water quality and sustainable fisheries in Burkina Faso. Fishermen took an active role in the project by informing scientists where to sample and how to perform traditional cast net fishing. Fish sorting and identification (up to species level) were done in the field. Fish that could not be identified at the species level were preserved in 70% alcohol and taken to the laboratory for identification by professionals (Melcher et al., 2020).

Mini Stream Assessment Scoring System (miniSASS) was developed in South Africa for citizen scientists to assess river health in South Africa (Dickens and Graham, 2002; Graham et al., 2004). The miniSASS was developed from SASS, which required users to have the ability to identify at least 90 macroinvertebrate families. A statistical evaluation proved that miniSASS and SASS gave similar results (Graham et al., 2004). It involved sampling macroinvertebrates in a river, identifying them in the field in broad categories, and then calculating the river health index. However, the volunteers use a dichotomous key, which is available only on the miniSASS website, and record results obtained on an online portal. Although a large amount of data can be generated from citizen scientists, the validity of this data may be a concern depending on the level of training the volunteers have been exposed to. MiniSASS has been applied in monitoring aquatic resources in Kenya, especially the ‘Adopt-a-River Initiative’ project, which exemplifies how key curricula components can be used to solve real challenges (Waswala et al., 2019). In this project, the public, especially the youth, are mobilized to manage the aquatic resources around them through the identification of polluted sites in the Nairobi River Catchment, with the aim of enhancing environmental regulations to ensure ecosystem health.

Elsewhere, several examples of successful citizen science monitoring do exist. The Anglers` Riverfly Monitoring Initiative (ARMI) is a citizen science project for water quality assessment in the United Kingdom (UK) (Brooks et al., 2019). Volunteers sample macroinvertebrates at each site once a month by kicking (for 3 min) habitats present at a site using a sampling net (250-mm frame and 500-mm deep net bag with 1-mm mesh). Large stones from the river bed are brushed in the mouth of the net to dislodge any organisms that have not been collected in the sampling net. Contents of the sampling net are emptied in a sorting tray, and macroinvertebrate taxa are identified and estimated to log₁₀ scale abundance. The macroinvertebrate taxa used as bioindicators the following: cased Trichoptera, caseless Trichoptera (caddisfy), Ephemeridae (mayfly), Ephemerellidae (blue-winged olive), Baetidae (olives), Heptageniidae (fat-bodied mayfly), Plecoptera (stonefly), and Gammaridae (shrimp). The choice of the taxa is based on ease of identification, range sensitivity to pollution, national applicability, present year-round (with the exception of Ephemerellidae), and is familiar to most anglers. A score is allocated to the log₁₀ abundance category for each taxon, and the scores of all the target groups are added. Volunteers are trained at a 1-day workshop before participating in the ARMI monitoring program. River coordinators for each catchment are in charge of organizing volunteers and uploading data onto the national database held at the Freshwater Biological Association, although some choose not to upload their data.

In Spain, RiuNet¹ was initiated by the Ecology Department of the University of Barcelona. Volunteers assess river water quality with simplified protocols available in the RiuNet handbook². Macroinvertebrates are identified at the family level using pictures or dichotomous keys available on the RiuNet app. Volunteers identify insects (Diptera, Coleoptera, Odonata, Heteroptera, Trichoptera, Ephemeroptera, and Plecoptera) and taxa from the Mollusca, Oligochaeta, Hirudinea, and Crustacea. Volunteers sample each site twice every year, in spring and autumn. The RiuNet app automatically calculates a simplified biological quality index. The RiuNet project does not have a training program for volunteers. However, citizen scientists learn from the RiuNet app, which guides them on how to assess the ecological status of a river.

Save-our-Streams (SOS) program is a citizen science monitoring program in the USA. The SOS program mainly focused on observations of water odor, color, and the presence of trash in streams. Macroinvertebrates were added to the monitoring program later on with the aim of assessing stream degradation (Engel, 2000). Virginia SOS sampling protocol has three kick net samples. A kick net of 1,500 μm mesh size is held in a rifle by a volunteer, and an area of 1m² is kicked in front of the net. The net is taken to the stream shore, where sorting and identification of macroinvertebrates are done based on previous training and simple pictures. Identification is mostly at the order level and, in some cases, at the family level. Data from each kick net sample is recorded in an assessment sheet, and then the SOS water quality rating score is calculated (each kick net sample is scored individually). Volunteers must undergo training and certification processes to participate in the monitoring program. The Department of Environmental Quality in Virginia signed a memorandum of agreement with the Virginia SOS program to use their data but with a quality control plan.

In river catchment management, local communities are key stakeholders, and their participation has been agreed upon as an important element in delivering water-related decisions (Rolston et al., 2017). However, sometimes bottom-up, community-led, catchment-based approaches to land and water management tend to provide new challenges to policymakers (Gurney et al., 2016) since community priorities may vary according to local values and pressures (Rolston et al., 2017). To advance citizen science in river water quality monitoring as a system health indicator, cheap, simple, easy-to-use approaches using the most common bioindicators are required and proposed in the following section.

Macroinvertebrates and fish are useful bioindicators of river health. The East African countries should embrace this approach as a block for easy comparison of the ecological status of rivers within the region, including the transboundary systems. The countries lagging behind, Kenya and Uganda, should develop their own indices and assessment tools using foundations from the already developed regional indices, such as TARISS from Tanzania. Enhancing citizen science in system health monitoring is the future management strategy for raising awareness, bridging the gap between users, policymakers, and scientific findings, and interpreting social-ecological information. This review advocates for the use of a community-based biomonitoring approach using macroinvertebrates and fish.

NK: Conceptualization, Data curation, Formal analysis, Investigation, Supervision, Validation, Visualization, Writing – review & editing. LO: Data curation, Formal analysis, Investigation, Writing – review & editing. PM: Data curation, Formal analysis, Investigation, Writing – review & editing. AB: Data curation, Formal analysis, Validation, Writing – review & editing. AM: Data curation, Formal analysis, Validation, Writing – review & editing. GS: Validation, Writing – review & editing.