River Flow 2014 – Schleiss et al. (Eds)© 2014 Taylor & Francis Group, London, ISBN 978-1-138-02674-2

Spatiotemporal patterns of geomorphological processes determine
characteristics of riverine habitat heterogeneity
M. Hyodo, Y. Takemon & T. Sumi

Disaster Prevention Research Institute, Kyoto University, Kyoto, Japan

ABSTRACT: Riverine habitat structure and its heterogeneity are determined by spatiotemporal patternsof geomorphological processes. However, only a few researches have quantitatively analyzed geomorphological changes and resultant spatial distributions of habitat structures in a shifting habitat mosaic. We
conducted a case study in a middle reach of the Tenryu River in Japan to identify how these changing patterns determine habitat heterogeneity. A set of interval-recording-cameras has been installed at 60 m above
riverbed on the electric supply tower located in the middle of the river corridor. Firstly, we identified different types of habitat structures in a reach and analyzed characteristics of flood inundation processes for eachhabitat type. Secondly, we analyzed, at a micro scale, hardening and softening processes of habitat structures,using a riverbed softness measurement. Thirdly, we developed a 2-D model using the photogrammetricmethod and quantitatively analyzed erosion and deposition processes at macro and reach scales.
1

InTroduction

Riverine habitat is structured with various habitat
types, e.g., riffles and pools, back waters, and side
pools, and these habitat structures are formed byerosion and deposition processes. Such geomorphological processes are determined by flood intensityand frequency, and sediment volumes with various grain sizes (Poff et al. 1997, Sumi & Kantoush2010), thereby characterizing habit diversity andheterogeneity. Depending on flow and sediment
regimes, habitats are recurrently created and eliminated and they are structured as a result of spatiotemporal patterns of geomorphological processes(Hyodo et al. 2013a). Habitat structures include
nutrients and vegetation and they are influenced byflow and sediment regimes as well (OCK et al. 2010,
OCK & Takemon 2011). In order to restore the riverine ecosystem, it is important that spatiotemporal
patterns be appropriately evaluated. However, current ecological evaluation tools, e.g., HEP (US FWS1981), PHABSIM (US FWS 1989), AUSRIVAS(Parsons et al. 2001), RIVPACKS (Wright et al.
2000), IBI (Karr 1981, Karr & Dudley 1981), etc.,
does not address this perspective. Recent researches
implicated that, in order to optimize biodiversity,
it requires presence of various habitat types withdifferent habitat age (Takemon 1997, Ward et al.
2002). For example, there are several researches
looking at spatiotemporal patterns of riverine habitats, e.g., shifting habitat steady state (Arscott et al.
2002) and habitat age (Tockner et al. 2010) in the
Tagliamento River. However, only a few researches

have tracked changing patterns of each habitat andquantitatively analyzed geomorphological changes
and resultant spatial distributions of habitats.
The objective of this study is to analyze spatiotemporal patterns of geomorphological processes
that determine characteristics of riverine habitat
heterogeneity. We analyze spatiotemporal patterns
from a perspective of flood inundation, riverbed
hardening and softening, and erosion and deposition processes.
2

Methodology

We conducted a case study in a middle reach of
the Tenryu River in Japan. The Tenryu River has
the catchment area of 5090 km2 and river lengthof 213 m in the Nagano, Shizuoka, and Aichi prefecture. The study area is at 16.4 k-point from its
river mouth, the slope is 1/520 to 1/650, 60% representative grain diameter is 60 to 73 mm, riverbed
configuration is co-exiting of alternate and braided
bars, and channel width is 1000 km. The lowest
dam at the downstream reach is called Funagira
dam located at 30 k-point for hydropower. A discharge gauging station has been set at Kashima at
25 k-point. There is an electric supply tower locatedin the middle of the river corridor. We have installedon the tower a set of interval-recording-cameras at
60 m above the riverbed since 8 August 2012, after
we conducted camera testing on 17 May 2012. The
study are and camera-recording sites, which are
directed to upstream and downstream, are shown2339

in Figure 1, and the photo data are shown in
Figure 2. A number of habitat types were identified
within the camera-recording sites at the beginningon 8 August 2012, summarized as: three riffles (2 inupstream and 1 in downstream sites, also referred
to as Rfs), six side pools (4 in upstream and 2 indownstream sites, also referred to as SPs), and threeback waters (3 in upstream and 4 in downstreamsites, also referred to as BWs). SPs and BWs areclassified by defining that SPs are disconnected tomain or secondary channels by surface water under
low flow conditions, and on the other hand BWs
are connected. Exceptionally, in case when surface
waters are connected but flow direction of pools
goes to main or secondary channels rather thaninfluenced by backwater, these habitats are classified as SPs in this article, i.e., Up-SP-2 and UpSP-3 in Figure 2. This classification was made byphoto data and field surveys.
This case study conducted the following bywhich how geomorphological processes determine
characteristics of riverine habitat heterogeneity is
discussed: to analyze inundation processes during
floods with different intensity via interval-­recording
cameras; to quantitatively analyze changing patterns of riverbed softness at a micro habitat scale;and to quantitatively analyze erosion and deposition patterns at a macro habitat and reach scale.
2.1

Figure 1. Study area and camera-recording sites,­Tenryu River.

Figure 2. Habitat distributions within the camera­recording sites at the beginning, as of 8 August 2012.

Inundation processes during floods

Two flood events with different intensity wereselected for the inundation analysis. Figure 3 showshourly discharge of recent years in relation to surveys conducted. It is noted that hourly discharge
at the Kashima gauging station is used throughout this article, when providing information relating to discharge. As maximum annual discharge
since 1939 to 2013 is 4500 m3/s, one is a small
flood occurred on 23 October 2012 with the discharge of 510 m3/s, and another is a middle flood
occurred on 16 September 2013 with the dischargeof 4900 m3/s. Reasons for selecting these two
floods were because not only they have different
flood intensity, but also a riverbed softness survey
was conducted around these periods to analyze
their relations. Sequence photos taken via interval­recording-cameras were used to analyze inundation processes including flow directions according
to water level rise.

Figure 3. Hourly discharge at the Kashima gauging station located at 25 k-point, in relation to surveys conducted.

2340

2.2

Changing patterns of riverbed softness
at a micro habitat scale

In order to analyze changing patterns of hardening
and softening processes of the riverbed, a riverbed
softness survey was conducted six times in total,i.e., three times in 2012 (12 September, 15 October,and 18 November) and three times in 2013 (16 July,
30 August, and 22 November 2013) as shown in
Figure 3. A small flood occurred during the former
three times in 2012, while a middle flood occurred
during latter three times in 2013. Methodologies
for this survey are that firstly a matrix was developed for each habitat, ranging from 3 to 12 longitudinally along and 3 to 16 laterally against flow
direction respectively, depending on the habitat
size. The riverbed softness was measured at lattice points in matrixes. The measurement is called“shino” and was made with a small steel pipe, of
which one edge is sharp. The sharp side edge ispenetrated into the riverbed with a certain loadby hand, and the depths under the riverbed surface were measured and recorded. For each lattice
point of the matrix, the penetrated depth below
the riverbed was recorded five times and their average values were used as the riverbed softness. Whenthe riverbed is soft, a value of the riverbed softnessshows a high number and vice-versa. In order tomeasure the riverbed softness, there is a tool called“Hasegawa riverbed cone penetration testing”.
Since numerous lattice points need to be continuously measured, easy-to-use shino was adopted toeffectively measure them in this study.
2.3

Erosion and deposition patterns
at a macro habitat scale

can be obtained based on the least squares methodby transforming more than 4 pairs of coordinate
target bench marks as (Xi, Yi, xi, yi) (i = 1, 2 …, n:n ≥ 4) to liner equations.
xi b1 + yi b2 + b3 − xi X i b7 − yi X i b8 = X i(2)

xi b4 + yi b5 + b6 − xY
i i b7 − yYi i b8 = Yi

(3)

In this case study, we have installed 8 target
bench marks having coordinate values withincamera recording sites, of which 4 were used fordeveloping a 2-D model, i.e., a set of orthogonal
images. Figure 4 shows an image of superposing an orthogonal image developed and aerial
photo taken both in December 2012. This result
describes well the accuracy of the 2-D modeland showed approximately the 1 m accuracy.
­Considering a fact that a river width of this study
area is about 800 m, this accuracy is appropriate
enough to quantitatively measure erosion anddeposition areas. However, it is noted that modeling of around photo edges used extrapolation
and reduced its accuracy. This fact does not discuss in this article, but will be treated as a futurechallenge to enhance accuracy of this model.
A period for the quantitative analysis was from
17 August 2010 to 16 December 2013 (see Fig. 3).
Even though interval-recording-cameras have been
installed since 8 August 2012, camera testing was
conducted prior to its installation on 17 May 2012.
This photo data enables to obtain geomorphologicalchange by a middle flood on 20 June 2012 with thepeak discharge of 3740 m3/s. In addition, orthogo-

Firstly, we developed a 2-D model applying a photogrammetric method, i.e., transforming photo data
to 2-D images with the orthogonal coordinate system, in order to quantitatively analyze erosion anddeposition processes (see also Hyodo et al. 2013b).
Secondly, erosion and deposition areas were measured by orthogonal 2-D images developed, whichwere superposed to identify geomorphologicalchanges of surface-terrestrial boundaries. Then
relations between flood intensity and erosion anddeposition processes were analyzed.
A basic theory of the photogrammetric methods is formed by an equation (1).
b x + b5 y + b6
b x + b2 y + b3
, Y= 4
X= 1
b7 x + b8 y + 1
b7 x + b8 y + 1(1)This equation is obtained from objectives to betransformed, which need to be a plane geometry,
but they do not necessarily be a non-plane geometry, e.g., vertical and slope planes. 8 unknown
quantities from b1 to b8 in equations of (2) and (3)Figure 4. An image of superposing an orthogonal image
developed and aerial photo taken both in ­December
2012.

2341

nal aerial photo data on 10 December 2011 and
17 August 2010 were used to obtain changes due toa large flood occurred on 21 September 2010 withthe peak discharge of 7520 m3/s. These orthogonal
aerial photo data were taken and developed by the
Hamamatsu Office of Rivers and National Highways, Ministry of Land, Infrastructure, Transport
and Tourism. Based on these data, geomorphological changes by a set of small, middle, and large
floods could be used for the quantitative analysis
on erosion and deposition processes.
3

RESULTS AND DISCUSSIONS

3.1

Inundation processes during small
and middle floods

Figure 5 shows upstream photo sequences of asmall flood from 22 October to 2 November 2012,
taken by upstream interval-recording-cameras. As
for Up-BW-1 and Up-SP-2, flood water passed
through old channels followed by its water levelrise. This old channel played a role as an active
channel during a small flood, referred to as a “lotic
system”. On the other hand, as for Up-SP-1, it
got inundated by backwater followed by its waterlevel rise around Up-Rf-1, referred to as a “lentic
system”. In simplification, habitats have different
inundation processes during small floods, which
can be categorized as two types of lotic and lentic
systems. Only Small geomorphological change has
occurred by the small flood, such as integrating
Up-BW-1 and Up-SP-2 into Up-BW-11.
Figure 6 shows upstream photo sequences of
a middle flood from 14 September to 3 October
2013. At an earlier stage of the middle flood, inundation processes are similar with small floods.
When the water level reached to the flood peak at
13:00, 16 September 2013, a part of woody cano-pies is above the water level except of which weretotally inundated. In the recession stage of floods,
river geomorphology appeared to have changed.
Habitats were newly created such as Up-Rf-21, 22
and 23, Up-BW-22, Up-SP-21, etc. This implicatesthat middle floods have the potential to create new
habitats, while small floods cause only geomorphological changes at a very small scale.
3.2

Changing patterns of riverbed softness
at a micro habitat scale in relation to floods

This section analyzes changing patterns of micro
habitat structures, focusing on the riverbed softness,and how their hardening and softening processes
are related to geomorphological and inundation
processes, which can be represented by lotic andlentic systems. Figure 7 shows results of a riverbed
softness survey conducted in September, October,and November 2012 and July, August, and November 2013. A middle flood occurred between Augustand November 2013. Higher the numbers indicate
the riverbed is soft and vice-versa.
As for Rfs, the riverbed softness is averaged­longitudinally, i.e., riffle head, middle, and tail. The
result shows that the riverbed has got continuously
hardened especially at riffle heads. The riverbedof Up-Rf-2 once got softened, but it again started
to get hardened. At Dn-Rf-1, unique change has
occurred. While the riffle head got harder, the tailbecame softer until November 2012 and then again
got harder. This process may be explained that
small floods can transport a small portion of sediment to limited distance downstream, since small
floods erode sediment at riffle heads and deposit iton their tails. For middle floods, we expected thatthey can deposit sediment on existing Rfs and its
riverbed gets renewed and softened, according ourassumptions (Hyodo et al. 2013b). However, rel-Figure 5. Upstream photo sequences of a small flood from 22 October to 2 November 2012.

Figure 6. Upstream photo sequences of a middle flood from 14 September to 3 October 2013.

2342

Figure 7.

Results of the riverbed softness survey. Higher the numbers indicate the riverbed is soft and vice-versa.

evant results explaining this assumption could not
be obtained from this survey. One reason for this isthat since we could not conduct the survey between
a middle flood in September 2013 and a relatively
small flood in October 2013, but could conduct
only after the small flood. As of November 2013,
renewing processes of habitats by the middle flood
may be completed and hardening processes by thesmall flood may have already started. These processes are discusses in Section 3.3.
As for SPs and BWs, the riverbed softness is averaged for each habitat. As shown in Figure 7, lotic
and lentic systems correspond to the riverbed softness. Habitats with lotic systems showed lower values of the riverbed softness mostly below 10 cm,
while those with lentic systems showed higher
mostly above 10 cm. Lentic systems of SPs and BWs
are inundated by backwater, assuming that in floodrecession stages fine sediment is likely to be deposited on their habitats. This explains why lentic systems showed the riverbed is softer than lotic systems.
On the other hand, even if habitat types are SPs andBWs, those of lotic systems have the harder riverbed
than those of lentic systems. This result also leads toan assumption that small floods induce a sediment
move of the riverbed of such habitats at a micro
habitat scale, causing erosion as same as Rfs. Giving
a detailed look at Up-SP-1 of lentic systems, the riverbed softness got higher over the period from 2012
to 2013, experiencing both small and middle floods.
Figure 8 shows softening processes of Up-SP-1, representing well how lentic systems deposit fine sediment and form the softened riverbed.

the orthogonalization of photo data were developed under conditions of low-enough flows. Areaof erosion and deposition means changes of terrestrial and surface water boundaries in plane shapes
above low-enough water levels.
A period between August 2010 and December
2011 experienced a large flood with the dischargeof 7520 m3/s. Large area of erosion and deposition
were identified. Up-Rf-1 was developed by deposition of up- and down-stream sides on the right bars
created. A new secondary channel was created on
the left bars due to deposition and neighbor ­erosion.
As a result of significant geomorphological changes,
bar waterfront was formed by the large flood.
A period between May 2012 and September 2012
experienced a middle flood with the discharge of3740 m3/s. relatively large geomorphological changes
occurred. Right bars were deposited and extended
to downstream, thus renewing Up-Rf-1. Secondary
channels on the left bars were deposited and eroded
further downstream, thus creating Up-Rf-2.
A period between August and October 2013 experienced a middle flood with the discharge of 4900 m3/s.
On the right bars, a large ratio Up-Rf-1 was replaced
by deposition with a new habitat of Up-BW-22.
A period between October and December 2013
experienced a relatively small flood with the discharge of 2120 m3/s. A tail of the bar waterfront
was eroded and shifted further downstream.
A set of these results explains that creation, elimination, renew of habitats can occur through erosion and deposition processes, and these changing
patterns can be characterized by flood intensity.

3.3 Flood intensity and erosion and deposition
processes at a macro habitat scale

3.4 Erosion and deposition processes extended
to a reach scale and discussions

Figure 9 shows a temporal series of spatial distributions of erosion and deposition areas withincamera photo frames upstream. 2-D models for

Figure 10 shows geomorphological changes at areach scale in August 2010, December 2011, andDecember 2012. After experiencing a large flood,2343

this reach has significantly changed the ­channel configuration, Up-Rf-1 was newly created as a result ofsuch significant change, and the bar waterfront wasformed as of December 2011. After experiencing
a middle flood, the channel configuration has notchanged, but changes to creating and renewing habitats have occurred at a macro habitat scale within the

Figure 8. Micro habitat photos of Up-SP-1. These
photos represent well how fine sediment is deposited by abackwater effect, leading to softened riverbed.

bar as of December 2012. When experiencing only
small floods, habitat changes at a micro habitat scale,for example Rfs get continuously hardened (seeFigs. 7 and 9). This result shows that geomorphological processes and resultant habitat heterogeneity
are characterized more or less by flood intensity.
Using the results of 2-D models developed(see Fig. 9), relations between flood intensity anderosion and deposition processes were analyzed.
We measured area of being eroded, deposited,unchanged, and surface water for each result.
Figure 11 shows relations between flood intensity and the area measured. In comparison withthe total area of 272,000 m2 for the analysis, in
relatively small and middle to large floods (larger
than 2000 m3/s), active area for geomorphologicalchanges, where erosion and deposition are subject
to occurring, is 19,000 to 89,000 m2 (17% to 33%
against the total area). On the other hand, in small
foods (lower than 1000 m3/s), active area is 4100 to
14,200 m2 (2% to 5%), explaining that small floods
less contribute to geomorphological changes.
In comparison with a ratio between erosion anddeposition area in small floods lower than 1000 m3/s
(see Fig. 11), erosion is dominant in most of cases.
During small floods, sediment adjacent to bar waterfront did not change. Based on this fact and hardening processes of the riverbed at riffle heads (asdiscussed in Fig. 7), it is assumed that sediment is not
supplied from upstream bars onto the riffle heads,
and within a riffle unit sediment is transported by

Figure 9. Results of orthogonalization of photo data, showing a temporal series of erosion and deposition areas,since 17 August 2010 to 16 September 2013.

2344

Figure 10.

Aerial photos at a reach scale in August 2010, December 2011, and December 2012.

eroding its heads and depositing it on its tails. This
process created the erosion dominant and hardeningof the riverbed at Rfs during small floods.
Taking an example of spawning redds for Ayu
fish species (Plecoglossus altivelis), it is known
that Rfs are important and they should be composed of relatively small gravels. Our recent studies
showed that especially riffle heads are more frequently used for spawning redds and soft riverbed
is one of important components creating suitableredds (Sumi et al. 2011). Our case study showedthat absence of middle and large floods reduces
the suitability by eroding riffle heads and showed
quantitatively processes of how the riverbed getshardened. It also showed that presence of middle floods create new Rfs and induce deposition
onto existing Rfs by a mass movement around bar
waterfront located upstream of riffles. Large floods
change significantly the channel configuration,
creating new Rfs as summarized in Figure 11.
As for Rfs, it is assumed that the Rf suitability can
be classified by flood intensity (see Fig. 11). Small
floods have a deterioration effect (-) by changing
habitats limited to a micro scale, middle floods havea relatively positive effect (+) by renewing riffle heads
by deposition of sediment within a macro habitat
scale, and large flood have a recovery effect (++) bysignificantly changing channel configuration andthus creating soften riverbed suitable for spawning
redds of Ayu species. As for SPs and BWs, small andFigure 11. Relations between flood intensity and riverbed erosion and deposition areas. This figure also depicts
geomorphological changing patterns and resultant SPs &BWs heterogeneity and Rf suitability.

middle floods enhance habitat heterogeneity overinundation processes of lentic and lotic systems,
while large floods may reduce habitat heterogeneity
by changing significantly the channel configuration.

2345

Although we need to accumulate data and anothereffect influencing suitability and heterogeneity, e.g.,timing and frequency of floods, vegetation effects,
etc., it is revealed that they can be explained by aspatial hierarchy at reach, macro habitat, and micro
habitat scales, and its temporal changing patterscaused by floods with different intensity.
4

Conclusions

Monitoring by a set of interval-recording-cameras
revealed that during small floods inundation processes of SPs and BWs are classified with two types oflentic and lotic systems and these systems determine
the riverbed softness at a micro habitat scale. Riverbed softness is high in lentic systems and low in lotic
systems. We developed a 2-D model applying a photogrammetric method. This model showed effectivenessto quantitatively analyze erosion and deposition processes with certain accuracy, by transforming photo
data to 2-D images with the orthogonal coordinate
system. This result showed large floods significantly
change channel configuration, as a result of which
new habitats are created. Middle floods do not havethe potential to change the channel configuration, butchange can occur at a macro habitat scale and renew
existing habitats such as Rfs by deposition within abar formed after large floods. Small floods can change
at a micro habitat scale, for example Rfs get continuously hardened. These results showed that geomorphological processes and resultant habitat suitability
and heterogeneity are characterized more or less byflood intensity. Even though we need to accumulate
data and another effect influencing suitability andheterogeneity, e.g., timing and frequency of floods,
vegetation effects, etc., it is revealed that they can be
explained by a spatial hierarchy at reach, macro habitat, and micro habitat scales, and its temporal changing patters due to floods with different intensity.
Acknowledgements
This study in the Tenryu River was supported bynumerous people and organizations. Acknowledgements are given particularly to the Kakegawa
electronic office of the Chubu Electronic PowerCo. Inc., Hamamatsu branch office of the C-tech
Corporation, Tenryu River Fisheries Cooperative,
Hamamatsu Office of River and National Highwayof the Ministry of Land, Infrastructure, Transport
and Tourism, and IDEA Consultants, Inc., Japan.
References
Arscott, D., Tockner, K. Nat, D., & Ward, J. 2002. Aquatic
Habitat dynamics along a Braided Alpine River­Ecosystem (Tagliament River, Northeast Italy), Ecosystems 5: 802–814, DOI: 10.1007/s10021-002-0192-7.

Hyodo, M., Takemon, Y. & Sumi, T. 2013a. Need foranalyzing patiotemporal patterns of river-corridor
habitat structure in sediment management, Advancesin River Sediment Research—Fukuoka et al. (eds),
pp. 1557–1567.
Hyodo. M., Awazu, Y., Takemon, Y., Sumi, T. &Deng, Z. 2013b. A geo-morphological monitoring method for analyzing riverine shifting habitat
mosaic, Annuals of Disas. Prev. Res. Inst., Kyoto
Univ., No. 56 B, pp. 699–712 [in Japanese with English synopsis].
Karr, J.R. & D.R. Dudley. 1981. Ecological perspective on water quality goals. Environ. Manage.
5:55–68.
Ock, G., Muto, Y., Sumi, T., & Takemon, Y. 2010. Rolesof Riffle and Pool Structure in Particulate Organic­Matter Dynamics in the Downstream Reaches of
Dam Reservoirs, Annuals of Disaster Prevention
Research Institute, Kyoto University, No. 53 B,
773–782.
Ock, G. & Takemon, Y. 2011. Relation of Hydrogeomorphology of Gravel Bar in Particulate Organic Matter
Dynamics in Braided Alpine River, Annuals of Disaster Prevention Research Institute, Kyoto University,
No. 54 B, 727–733.
Parsons, M., Thoms, M., & Norris, R. 2001. ­AustralianRiver Assessment System: AusRivAS Physical­Assessment Protocol, National River Health Program,Environmental Australia.
Poff, N.L., Allan, J.D., Bain, M.B. & Karr, J.R., 1997.
Prestegaard, K.L., Richter, B.D., Sparks, R.E. andStromberg, J.C.: The natural flow regime, BioScience
47, No. 11, pp. 769–784.
Sumi, T. & Kantoush. S.A. 2010. Integrated ­Managementof Reservoir Sediment Routing by Flushing,­Replenishing and Bypassing Sediments in ­JapaneseRiver Basins, 8th International Symposium on­Ecohydraulics, CD-ROM.
Sumi, T., Nakajima, K., Takemon, Y. & Suzuki, T. 2011.
Evaluation of suitable river morphology for spawingof Ayu-fish, Annuals of Disas. Prev. Res. Inst., Kyoto
Univ., No. 54 B, pp. 719–725 [in Japanese with English
synopsis].
Takemon, Y. 1997. Management of biodiversity in aquatic
ecosystems: dynamic aspects of habitat ­complexity
in stream ecosystems. In: (ed. by Abe T., Levin S., &Higashi M.) Biodiversity: An Ecological Perspective.
Springer, 259–275.
Tockner, K., Lorang, M.S. and Stanford, J.A.: Riverflood plains are model ecosystems to test general hydrogeomorphic and ecological concepts, River research
and applications 26, pp. 76–86, 2010.
U.S. Fish and Wildlife Service. 1981. Standards for thedevelopment of habitat suitability index model foruse in the Habitat Evaluation Procedures, USDI Fish
and Wildlife Service, Division of Ecological Services.
ESM 103.
U.S. Fish and Wildlife Service. 1989. Physical Habitat
Simulation System Reference Manual Version II.
Instream Flow Information Paper No. 26.
Ward, J.V., Tockner, K., Arscott, D.B. & Claret, C. 2002.
Riverine landscape diversity, Freshwater Biology 47,
pp. 517–539.
Wright, J., Sutcliffe, D. & Furse, M. 2000. Assessing thebiological quality of fresh waters: RIVPACS and othertechniques, Freshwater Biological Association.

2346