Criteria and Process for Selecting Study Sites in River Ecosystem Research

1. SELECTION OF STUDY SITES Jay O’Keeffe, UNESCO-IHE Institute for Water Education

2. Study Sites • BBM sites are the focus for (almost) all data collection activities • An EFR is set for each site (one per section), therefore: • Each site should provide greatest range of possible environmental conditions • These conditions are represented in a manner acceptable to all involved specialists • Staff involved in site selection should have experience in BBM site selection

3. Data Sets • Usually more than one site is selected • Tributaries may introduce different channel, bank or habitat conditions affecting ecology • The EMC may differ for different river stretches • Natural transition of plant and animal communities along river • Number of sites is a trade-off between better representation () and a more lengthy, more complicated and more expensive process ()

4. Minimum and ideal data sets • Minimum data set depends on size and complexity of study area, • additional considerations are: • Most specialists can spare some 4 days in workshop • One group of specialists can address 4 sites • Four sites, if chosen well, can represent 100-200 km • Required no. of sites depends on diversity of system • Always one site per river section! • Ideal data set: two sites for each river section

5. Sequence of activities • Aerial study to aid site selection • Identification of potential sites using video • Groundtruthing: final site selection

6. Key criteria for site selection • Easy access • High diversity of physical habitats • Flow-senstitive & critical habitat for important species • Suitable for accurate hydraulic modeling • Close proximity to gauging weir • Potential to provide useful EFR information (location relative to WRD)

7. Key criteria for site selection (cont.) • Positioned upstream of major tributary • Good ecological condition (to enable flow-related clues to aid understanding of flow effects on eco-system • Close proximity to rural communities that use river resources for sustenance • Potential as future monitoring site

8. Key criteria for site selection (cont.) • Sites should be selected to be representative of a river section, but • it is more important that sites should be at a critical point in the section and exhibit flow dependent features

9. Characteristics of unsuitable sites • Located on a bend • Located in relatively featureless sandy stretch • Consists mainly of large pool • Locate in inaccessible gorge • Impossibility to model hydraulics, in spite of excellent habitat diversity • Several team member consider site unsuitable

10. Placement of river cross-sections • Locations of cross sections represent the site • Required information • Channel dimensions • Other data, including, but not limited to • Boundaries of vegetation zones • Substratum and other details on physical habitat • Vegetation • Coding: • Each site has code number (most upstream: BBM site 1) • Cross section designated with letters (most upstream: A)

11. Other Fieldwork • During site visit, some data can be collected • Cross-section dimensions and details • Fixed-point photography • Hydraulics • Fluvial geomorphology • Riparian vegetation • River health and aquatic invertebrates • Fish survey

12. Surveying cross sections • Objective is to determine: • Stage-discharge relationship • Position of vertical vegetation zones up the banks • Position of key plant species in these zones • Position of key geomorphological features (to establish the flows that inundate them)

13. Site selection report • Report forms part of workshop starter document • Contents • Purpose of the sites • Selection of the sites • Study area, selection of river stretches, helicopter flight, use of aerial video, field visit: final selection of sites • Characteristics, advantages and disadvantages of each site • Final site selection

14. Fig 7.1 BMM sites located in river sections