Rufiji Basin, Tanzania
COMPLIANCE MONITORING FOR THE ABSTRACTION OF IRRIGATION WATER
KEY CHALLENGES
The Rufiji River Basin drains an area of 177'420 square kilometers, which makes it Tanzania's largest river basin by area and discharge. Large hydropower facilities are located in the downstream, making efficient water use in the upstream a national interest. The basin also has significant environmental assets that include four national parks, six game reserves, one marine park, and over 100 forest reserves. With a population of 3.6 million, the basin lies at the heart of the Southern Agricultural Growth Corridor of Tanzania and is earmarked for major agricultural development based on its conducive climate, large water bodies and vast arable land.
Among the key challenges faced by the basin is the paucity of reliable water resources data which makes it difficult to perform evidence-based water resources planning, development, and management. The underlying causes of this problem are diverse. I.e. the large basin size makes it costly and time consuming to operate an optimal density of monitoring stations, significant capital investments are needed to enlarge the monitoring network, large protected areas only allow limited access and poor operation and maintenance of existing monitoring stations lead to data gaps.
NEEDS
Several large scale abstractors with properly constructed intakes are supposed to comply in terms of their abstracted volumes with their respective water use permits. These permits define daily maximum withdrawn quantities and respective annual fees to be paid to the basin office. None of these intakes are continuously monitored as water abstractions are measured only once or twice a year at most, during control visits of the basin authority. For these control measurements, three hydrologists of the basin travel to the respective intakes and measured the discharge with a flow-meter during the transition from wet to dry season. Due to the enormous size of the basin, the significant operational costs of these measurement campaigns limit the amount of intakes that can be monitored and the monitoring frequency alike. What is needed is an improved way for compliance monitoring, i.e. one that is affordable and scalable.
IMPLEMENTATION
discharge.ch is the technology of choice for the Rufiji Basin to measure intake flow volumes on a daily basis through local involvement. During the pilot phase of three month, 16 irrigation intakes with existing water use permits at different tributaries of the Rufiji river have been calibrated so that they can be measured on a daily basis by members of the local Water User Associations (WUA). Legal contracts between the community-based data collectors and the RBWO were drafted to clarify responsibilities such as e.g. measurement time and frequency, etc. for each site. These contracts did not include any payments for the crowd-senders since the compliance monitoring already is part of their responsibility as WUA members.
RESULTS
The ongoing campaign to measure irrigation abstraction volumes is successful since it answers needs from all stakeholders. The irrigators want to know whether they get the water for the amount of money they pay and the authority is interested in getting the proper amount of money for the water that is utilised by the irrigators.
discharge.ch is the technology of choice for the Rufiji Basin to measure intake flow volumes on a daily basis through local involvement. During the pilot phase of three month, 16 irrigation intakes with existing water use permits at different tributaries of the Rufiji river have been calibrated so that they can be measured on a daily basis by members of the local Water User Associations (WUA). Legal contracts between the community-based data collectors and the RBWO were drafted to clarify responsibilities such as e.g. measurement time and frequency, etc. for each site. These contracts did not include any payments for the crowd-senders since the compliance monitoring already is part of their responsibility as WUA members.
The figure shows the collected daily discharge data during the transition from wet- to dry season 2017 (Note: names and locations of individual not disclosed due to the sensitivity of the data). The blue lines indicate that during the wet season (March to June) intake A, B and D were complying with agreed abstraction permits (red dotted lines) while intake C did not. The measurements further show that during the dry season (June-October) only intake D seems to comply with its agreed abstraction rate. To which extend intakes are manually adjusted according to their permit and to which extend the decreasing abstraction is a consequence of decreasing flows in the natural streams is a relevant question which arises and should be further investigated.