Resource Directed Measures for Protection of Water Resources: River Ecosystems
R22:
PROCEDURE FOR SELECTING SITES IN INTERMEDIATE AND COMPREHENSIVE
DETERMINATION OF THE ECOLOGICAL RESERVE (WATER QUANTITY COMPONENT)
Senior Editor:
Delana Louw, IWR Environmental
Contributing Authors:
Nigel Kemper, IWR Environmental
Andrew Birkhead, Streamflow Solutions
Editor:
Heather MacKay, Department of Water Affairs and Forestry
Lizette Guest, Guest Environmental Management
Version:
1.0
Date:
24 September 1999
M:\f_rdm_october\rivers\version 1.0\riv_appR22_version1.0.doc
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Appendix R22:
Procedure for Selecting Sites in Intermediate and Comprehensive
Determination of the Ecological Reserve (Water Quantity
Component)
The process for determining the Ecological Reserve (ER) (Quantity) differs according to the level of
determination required such as Intermediate or Comprehensive. Related to this is the level of detail required
within the site selection. Within this document, reference will be made to these two different levels where
applicable.
NB. The flow component of the Ecological Reserve is referred to in this document as the Instream Flow
Requirements (IFR)1.
R22.1 Role of IFR sites in quantification of the flow component of
the ecological reserve.
The ER (Quantity) is determined during the a specialist meeting where descriptions of flow in parameters such
as depth, velocity and water surface level linked to habitat requirements are stipulated. These parameters need
to be converted to flows by means of a stage discharge curve for a specific cross-section (See Appendix R17)
determined by a hydraulic modelling procedure. These descriptions of flow requirements take place at a
specific cross-section/s in the river called an IFR site. To enable the IFRs to be calculated, these IFRs sites
should answer to many criteria, the most important being that the sites should represent critical and varied
habitats.
The selection of the IFR sites forms the basis of the preparatory work to be undertaken for the IFR specialist
meeting.
The water quantity component of the Reserve is set for each of the IFR sites, and it is therefore vital that
 the sites are selected to provide as much information as possible about the variety of conditions in a river
reach
 that the specialists that need to use these sites to set IFRs for their discipline can relate to the habitat the
sites represent.
 the persons involved in selecting the sites understand and are experienced with the use of sites in IFR
studies. (Louw & Kemper 1997)
Therefore, In order to determine the ER of a river, the IFRs at a number of IFR sites need to be determined.
R22.2 Minimum data sets
More than one IFR site is usually selected within the system for a number of reasons:
 Tributaries entering the system may introduce different channel, bank and/or habitat conditions which may
need to be considered separately.
 The Ecological Management Class (EMC) of particular reach of the river may differ.
 A river system displays biological diversity along its length, and consequently, a single IFR site is unlikely
to adequately reflect this range of diversity.
 Various hydrological stage points are required within the system to cater for the inflows of tributaries and
losses down the length of the system.
Editor’s note: Terminology to be resolved for version 1.1 – use of “IFR” is inconsistent throughout this
document.
1
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The confidence of the quantification of the ER is related to various aspects, including the number of IFR sites
representing a river reach, and the adequacy of the sites in setting flow. The number of IFR sites in the system
influences the cost and time required for the study, especially when it comes to components such as hydrology
and hydraulics. The length of the specialist meeting is also influenced by the number of the IFR sites.
The decision as to how many sites are selected is therefore
 a function of the length and diversity of the river to be assessed;
 a trade-off between the need to characterise the river adequately and the constraint of time and resources
available.
 a function of the method (Comprehensive or Intermediate) used to quantify the ER.
The limitations of setting flows at individual sites is offset by the general overview of the river provided by
other studies forming part of the ER such as the habitat integrity assessment (See Appendices R4 & R5).
The number of IFR sites required for a CER depends on the size and complexity of the study area. However,
the following general principles can be applied:
 Four IFR sites are usually selected as the number that can be accommodated during a one group four day
specialist meeting (CER).
 Based on the experience of IFR specialists, four IFR sites, selected correctly, will normally cater for a river
length of 100 - 200 km (CER).
 A shorter stretch of river does not necessarily imply fewer IFR sites. The number of sites selected will
depend on the variety of habitats and reaches in the stretch of river to be assessed.
The selection of four sites falls within the time constraints associated with the Comprehensive ER (CER)
following the Building Block Methodology (i.e. 8 months) pending the season when the study is initiated. The
sites must be selected during the low flow season and if a study is initiated during the high flow season, the site
selection will be delayed until the low flow season.
The CER will be applied for large and/or important rivers. The Intermediate Ecological Reserve Methodolgy
(Quantity) (IERM (Quantity)) will probably be applied more often for smaller rivers and smaller developments.
The IERM (Quantity) is essentially a scaled down version of the BBM. The same principles for site selection as
for the BBM are followed, however the process linked to the IERM will be scaled down. The impacts on flow
of smaller developments (for which an IERM would most likely be applied) would be apparent for a shorter
stretch of river than where large developments are being planned (as for a CER). It is therefore assumed that
two IFR sites will be selected during an IER for a river reach of between 70 and 100 km in length. This
decision will be based on the results of step 1, 2 and 4 of the ER process and is therefore an ad hoc decision that
will depend on the specific impact of the development amongst others.
R22.3 The selection of IFR sites
The IFR site selection is usually managed by the IFR co-ordinator, although a specialist who is familiar with the
process could manage the site selection process. For the purpose of this chapter it is assumed that the IFR coordinator undertakes the process.
To manage the IFR site selection, the IFR co-ordinator must
 have previous experience of the use of the IFR sites in an IFR workshop;
 have a basic understanding of all the disciplines involved with IFR sites and the specific requirements and
expectations of the specialists for IFR sites.
 be able to weigh up the advantages and disadvantages of the different sites and all relevant factors and make
an informed decision on which sites to select during the IFR site visit.
The site selection process during the CER (Quantity) is undertaken by a site selection team consisting of the
following specialists:
 Co-ordinator
 Fish
 Aquatic invertebrates
 Riparian vegetation
 Fluvial geomorphology
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
Hydraulics
The above representation is required to ensure that sufficient clues for each component are present at the IFR
sites to enable quantification of the requirements. This leads to the site requiring ecologically diverse and
sensitive habitats. However, the hydraulic accuracy of the site is the most important factor, and hydraulic
accuracy is usually linked to simple canal-like structures. The process of selecting sites is therefore a negotiated
process whereby ecological variability and confidence has to be measured against hydraulic accuracy. If, a
good ecological site is selected but with resulting low confidence hydraulics, the specialists can be very accurate
and confident about their requirements, but with inaccurate hydraulics, the resulting recommended flows could
be meaningless.
For the purpose of the IERM (Quantity), it is recommended that the BBM site selection principles are utilised
wherever possible when selecting the IFR sites, but it is acknowledged that a video is unlikely to be available in
most cases, and sites will be selected based mostly on the accessibility of sites, within the time constraints. Due
to the lack of time available prior to the specialist meeting only one hydraulic calibration (compared to 3 or
more within the CER process), over and above the observations made during the site selection visit, will be
possible. However, the value of the second calibration will depend on how different the two calibrations are as
within a period of two months (the time scale for determining the IER), very similar flows could be experienced.
The site therefore has to be as hydraulically simple as possible to facilitate modelling of the hydraulic
relationships from possibly a single site observation, but should still provide as many ecological clues as
possible, i.e. provide a variety of habitats at different flows. IERM sites will therefore be less complex
(hydraulically and ecologically) than sites that can be selected during the CER process (Louw & Birkhead,
1998).
As the IERM (Quantity) is a 'scaled-down' version of the BBM, the same effort cannot be applied when
selecting sites. The site selection team will therefore be undertaken by two specialists only:
 Hydraulician
 An aquatic scientist (preferably the specialist that forms the coordinating task in the CER) with a basic
understanding of the habitat requirements of the various biotic components and of the river's functioning.
This person will require experience of BBM site selection and specialist meetings to understand the criteria
most often used in selecting sites by the fish, aquatic invertebrate, riparian vegetation and fluvial
geomorphological specialists. It would be an advantage if this person were one of the specialists. However,
it must be noted that only specialists that have been exposed often to IFR site selection understand how the
other specialists evaluate sites. Fish and invertebrate habitat might be seen as the more vital habitat as these
habitats are mostly used to set the base flows. All previous IFR results have indicated that the base flow
component forms the largest part of the total IFR flow volume, and higher flows/floods the smaller
component (in perennial rivers); it is therefore more important to have the base flows as accurate as
possible.
The selection of IFR sites is guided by a number of considerations, including (Louw & Kemper 1998). (The
criteria in boldface are the most important and therefore the overriding criteria):
 The locality of gauging weirs with good quality hydrological data.
 The locality of the proposed and existing developments.
 The locality and characteristics of tributaries.
 The habitat integrity or Present Ecological State (PES) of the different river reaches.
 The boundaries of Level II ecotypes within the study area
 The reaches where social communities depend on a healthy river ecosystem.
 The suitability of the sites for follow-up monitoring.
 The habitat diversity for aquatic organisms, marginal and riparian vegetation.
 The suitability of the sites for accurate hydraulic modelling throughout the range of possible flows,
especially low flows.
 Accessibility of the sites.
 An area or site that could be critical for ecosystem functioning. These are often represented by riffle
units, where low flow conditions or the cessation of flow constitutes a break in the functioning of the
river, and consequently, the biota dependant on this habitat and/or perennial flow are adversely
affected. Pools are not considered critical habitats in perennial system since they are still able to
function or at least maintain life during periods of no flow (Louw & Birkhead, 1998).
 The locality of geomorphologically representative sites.
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When selecting IFR sites, the following sequence of events is followed.
 Define the significant resource (previously described as the IFR study area, now covered by step 1 of the
ER procedures.
 Select river stretches in which IFR sites should be situated.
 Preliminary selection of possible IFR sites by means of a video (CER) or maps and local knowledge
(IERM), i.e. desk-top only.
 Ground-truthing of possible sites leading to the final selection.
 Determine cross-sections at the IFR sites.
 Document the reasoning behind the selection process.
 Undertake a cross-sectional survey.
Each of the above events will be discussed separately.
R22.4 Sequence of events for the selection of IFR sites
R22.4.1 Define the significant resource
This step is covered as part of the ER process and described in the Integrated Manual. The study area should be
illustrated on a basic map which is used throughout the ER determination and should depict the following:
 5 km habitat integrity sectors if relevant
 Level II ecoregion breaks
 Locality of existing and proposed developments
 Gauging weirs
 Biomonitoring sites if relevant
 Locality of IFR sites
 Virgin vs Present Mean Annual Runoff (MAR) at various points in the system.
R22.4.2 Selecting a length of river (IFR stretch) in which an IFR site should be situated
Appendix R2 describes the terminology for different parts of rivers on the basis of geomorphology (zone,
segment, reach etc). IFR stretches2 are parts of rivers which may or may not correspond to the
geomorphological breakdown of the river, and will be chosen according to specific criteria. An IFR site will be
selected in each IFR stretch.
The selection of river stretches is guided by similar considerations as those that influence the site selection.
The IFR stretches are identified by the IFR co-ordinator on a map with input from the hydrologist,
geomorphologist and river ecologists with knowledge of the study area. These stretches will be presented to the
IFR planning meeting and motivated by the IFR co-ordinator during the CER process. During the IER, local
knowledge will be used only as this information is required upfront, prior to any other information becoming
available. During the CER, the IFR stretches need to be selected prior to the habitat integrity helicopter flight,
the IFR planning meeting and the site selection.
An example of how the IFR stretches were described for the CER determination for the Mvoti River is as
follows:
Stretch 1 : Downstream of Mvotipoort Dam and upstream of the Sikoto Tributary.
Stretch 2 : Downstream of the Sikoto Tributary and upstream of the Situndu Dam site.
Stretch 3 : Downstream of the Hlimbitwa Tributary and upstream of the Welverdiend Dam site.
Stretch 4 : Downstream of the Welverdiend Dam site and upstream of the estuary.
2
Editor’s note: Author to check use of the colloquial term “stretch”
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R22.4.3 Preliminary selection of IFR sites
Determining where possible sites are located in rugged and undisturbed surroundings can be a difficult,
frustrating and time consuming process. Most of the small access roads in rural areas are not marked on maps,
and driving to all possible access routes on both sides of the river, could double the site selection costs, or the
sites selected might not necessarily be the best available. It is seldom possible to get a comprehensive overview
of a river from a ground survey.
The process of selecting IFR sites can therefore be aided by means of a helicopter flight which is usually
undertaken for the Habitat Integrity analysis during the CER process (Appendix R5) and capturing the river on
video. During this flight, the locations of potential IFR sites are recorded using a GPS (Global Positioning
System). Somebody in the helicopter should identify and mark possible access routes with possible sites near
the access routes. It is advisable for the navigator to do this function since he/she will be situated in the
helicopter to have a good view of the river and immediate catchment.
This helicopter flight should take place before the IFR planning meeting and site selection, approximately
within the first one and a half months of the study. Most important however is that the flight is undertaken
during LOW FLOWS. During high flows, possible sites are inundated and therefore not visible.
From the helicopter survey, a video is available and a GPS database of latitude and longitudes for every 4
seconds of the flight. Any area identified when watching the video can be accurately pinpointed on a map.
The video is viewed by the IFR site selection team to scrutinise the IFR stretches and sites identified during the
flight. The objective of this is to eliminate possible IFR sites and to streamline the next step in the process, i.e.
the identification of the sites on the ground.
This preliminary IFR site selection is usually undertaken the day before the site selection visit, sometime within
the first month and a half of the study period. For cost-effective reasons, the IFR planning meeting (which
requires more persons to attend than the site selection team, but includes the site selection team) is held in the
morning, followed by the preliminary site selection by means of the video and followed the next day by the site
selection visit.
During the IER process, the availability of a video is unlikely. However, due to the value of such a video, all
possible effort must be made to obtain this. If however a video is not available, the access routes on 1:50 000
maps, local knowledge and time constraints will guide the process.
R22.4.4 Ground truthing - final selection of sites
The preliminary site selection process by means of the video is followed by a site selection visit by the site
selection team to identify sites on the ground (CER). Each of the sites selected by means of the video is visited
and the advantages and disadvantages of the sites discussed. After viewing the possible IFR sites a site is
selected. This process can be time consuming and tiring and the site visit must be well structured with all
persons knowing exactly what is expected from them at the site and how much time they have for investigation.
The time required for the site selection visit depends on the locality of river and the ruggedness of the terrain.
Normally, 3 days (excluding travel) are sufficient to select 4 sites. It is important that time limitations do not
become the overriding consideration for site selection. Considerable additional costs will be incurred if the sites
are proven to be unsuitable for IFR determination at the workshop.
During the IER, the ground truthing is constrained to visiting areas that are readily accessible within the time
constraints. Since only two calibrations of the hydraulic rating curve may be undertaken, significant emphasis
must be placed on the hydraulic suitability of the sites. The site, however, must nevertheless contain sufficient
biophysical indicators for the setting of the flow requirement.
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R22.4.5 Placing of cross-sections
After the site is selected, the exact positions of the cross-sections have to be determined. This is also done on a
multi-disciplinary basis, with the hydraulics being the overriding factor. Sometimes more than one crosssection is required for use by different disciplines, but often the cross-sections required for hydraulic purposes
also serve to accommodate the requirements of the different disciplines. During discussions on site it must be
clearly established which cross-section will be presented at the worksession with stage discharge curves and all
the detail required.
Information required from the cross-section must be discussed and will often include riparian vegetation types,
surveyed trees, instream habitat types and substratum types. Some investigation by the specialists is often
required, especially of the far bank. These investigations should not take longer than half an hour before a
decision on the cross-sections is made.
The reference number of the IFR site and each cross-section must also be allocated on site as the benchmarks for
the cross-sections put in by the surveying team must reflect this. The most upstream site is IFR 1 and the sites
are numbered consecutively downstream. The cross-sections for each site are designated A for the most
upstream cross-section and B for the next downstream one etc. (E.g. IFR site 1 may have 3 cross-sections
numbered 1a (upstream), 1b (middle) and 1c (lower)).
The IFR sites for the IERM should be hydraulically simpler and one cross-section should suffice. This is
important as in this process, the hydraulician and aquatic assistant selecting the sites immediately also undertake
the cross-sectional survey. Available time and cost will not allow for numerous cross-sections to be selected.
R22.4.6 Fieldwork required during site selection
Some fieldwork is normally undertaken after the site has been selected. This is not a requirement of the site
selection process, but has been proved to be the most cost-effective way for the different disciplines to
undertake the field work (CER), as they are already on site. Since a flow measure is undertaken by the
hydraulician, the specialists’ biological findings can be linked to flow. The type of work usually undertaken is
listed below, details are given in the appendixes for each relevant discipline:
 Hydraulics : As hydraulic calibrations of a range of flows are vital to the IFR process, this is a valuable
opportunity to undertake a flow measurement and water level survey.
 Photo point monitoring: Photos of a variety of known or measured flows are used extensively at the
specialist meeting and whenever flow measurements are undertaken, photos of the cross-section at fixed
points should be undertaken. (The guidelines for the fixed photopoint monitoring are discussed in
Appendix R17)
 Riparian vegetation: The riparian specialist should mark and number trees for inclusion in the crosssectional survey. As the cross-sectional survey usually takes place immediately after the site selection, this
may be the only opportunity.
 Aquatic invertebrates : SASS survey
 Fish survey : E.g. electro fishing. Time may not available to do a detail fish survey.
 Fluvial geomorphology : E.g. measurement of hydraulic biotopes across the cross-section, sediment
sampling and a characterisation of the site and reach.
After the site and cross-sections have been selected, 2 hours are usually set aside for the above work.
Within the IERM, only the following will be possible to undertake at site as all disciplines are not represented:
 Hydraulics : Cross-sectional survey, flow measurement, water level survey.
 Photo point monitoring.
 Survey and marking of trees.
R22.4.7 Surveying of the IFR sites
After the IFR site selection (only applicable for the CER), cross-sectional surveys are undertaken at the IFR
sites. This is done by a survey team under supervision of a hydraulician and with input from the riparian
vegetation and fluvial geomorphology specialists. They indicate exactly which vegetation species and other
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features they want reflected on the cross-section. The cross-sections are then prepared for the following
purposes:
 To indicate where various zones and species of riparian vegetation occur.
 To indicate where specific geomorphological features occur in order to establish required flows for various
purposes e.g. bankful discharge.
 To establish a stage discharge relationship.
This information is then presented to the workshop for identification of IFRs at the sites.
Detail of the survey guidelines is discussed as part of Appendix R17.
R22.4.8 Reporting of the IFR site selection process



The above process is documented to serve as a record of decision-making as a
chapter in the specialist meeting starter document (CER)
chapter in the specialist meeting report (IERM).
Specific information for each site is required by each discipline, and the IFR co-ordinator that will write the
report should obtain this information from the specialists. Forms are therefore provided to all the specialists to
complete after each site has been selected. These forms are filled in during the site visit, collected and utilised
to document the following information for each site:
IFR 1 :Site name __________ (the name is derived from a relevant name on the map or some specific section of
the river or any arbitrary name which the specialists will relate to)
Coordinates : S _______E __________
Locality :
Advantages:
General
Invertebrates
Fish
Fluvial geomorphology
Hydraulics
Disadvantages:
General
Aquatic invertebrates
Water quality
Fish
Riparian vegetation
Geomorphology
Hydraulics
The contents of the site selection report include the following:
 Purpose of IFR sites
 selection of IFR sites
IFR study area
Selecting river stretches in which IFR sites should be situated
Helicopter flight to select IFR sites
Use of the river video for the identification of possible IFR sites
Ground truthing - final selection of sites
Placing of cross-sections
IFR 1 :
IFR 2 :
IFR 3 :
IFR 4 :
 Characteristics, advantages and disadvantages of IFR sites
IFR 1
IFR 2
IFR 3
IFR 4
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
Surveying of the IFR sites
The report should include figures such as the map described in R22.4.1. This document should be written as
soon as possible after the site selection visit so that it can be distributed to the team while the information is still
fresh in their minds.
R22.5 Pitfalls
The following are some of the examples of sites selected in areas that were problematic to use during the IFR
specialist meeting (Louw & Kemper, 1997). The sites were usually located
 on bends;
 on sandy stretches;
 on pools;
 in gorges.
Other reasons were that
 the sites were excellent ecological sites but poor hydraulic sites;
 the selection was not a consensus process and led to problems at the workshop as the full team could not
utilise the sites;
 the site selection team was too large and time and discussions on site became unwieldy;
 specialists were not trained in the use of IFR sites in the IFR workshop;
 budget problems exists;
 the river was so degraded that suitable sites with sufficient criteria could not be located;
 the river is alluvial and instream specialists find it difficult coupling requirements to sand habitats;
 the river is seasonal and dry during site selection.
When dealing with a river that has characteristics different to that experienced in IFR specialist meetings, it can
happen that sites selected are not suitable. This only however becomes apparent during the IFR specialist
meeting when all knowledge of the river is available and is applied to the IFR sites.
References
Louw, M.D. & Kemper N.P. 1997. Site selection for the BBM process. Unpublished chapter of BBM manual
Louw, M.D. & Kemper N.P. 1998. Mhlathuze River site selection. Draft DWAF report.
Louw, M.D. & Birkhead A.L. 1998. Crocodile River Preliminary Reserve : Site selection process.
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