RIVER HYDROMORPHIC ASSESSMENT,

TYPING AND RECONNAISANCE AND THE

SCIENTIFIC CHALLENGE OF RIVER SCALE

AND HETEROGENEITY

David Gilvear, University of Stirling

(Co-authors - Martin Thoms and Victoria Milner)

River Science Workshop – 18th April 2011

1. The context

2. The evolution: 4 phases

3. Case studies from the River Science phase

4. Future challenges: scale and heterogeneity

5. Conclusion

PRESENTATION STRUCTURE

CONTEXT

River appraisal, typologies and reconnaissance

involve the mapping, classifying and auditing of

rivers to determine their hydromorphological or

eco-morphological condition and human induced

changes in morphology and fluvial processes that

cause physical habitat degradation.

Definition

1. River systems are complex, branch-like systems that

convey water and episodically sediment and contain

interactive habitat mosaics at multiple scales.

2. There are an array of spatial units, of differing size

and in many cases nested on top of each other,

which exchange mass, energy and organisms. – the

hierarchial patch framework of Frissell et al. (1986).

3. Large-scale gradients exist as conceptualised by

Vannote et al. (1980). Stanford and Ward (1993)

also showed how stream channels interact with

floodplains together with the underlying hyporheos

River System complexity

River System complexity

River System Complexity

“The biophysical complexity (heterogeneity) of rivers underpins their

long-term vitality”

Naiman, 2006

THE EVOLUTION: 4 PHASES

Publications per year

0

20

40

60

80

1993

1995

1997

1999

2001

2003

2005

2007

2009

Year

No

of

pu

bli

cati

on

s

River+typology

Catchment+appraisa

l

Hydromorphology

and assessment

River habitat and

survey

River habitat and

remote sensing

Data obtained from Web of Science

THE PIONEERING PHASE (Pre 1970)

Davies (1899) Classification of the changing

character of river geomorphology in to

youthful, mature and old.

Horton (1945) First attempt at stream ordering of the

river channel network

Leopold and Wolman (1957) Classification of channels in to

meandering, straight and braided in

relation to slope and discharge

Strahler (1957) Amendment to Horton stream

ordering approach

THE ESTABLISHMENT/

THEORETICAL PHASE

1970 - 1990

Kellerhals et al. (1976) Classification of channels according to

patterns and lateral instability

Stocker and Williams (1972) Freeze coring substrates

Rust (1978) A classification of alluvial channels

Smith and Smith (1980) Classification including anastomosing

channels

Church (1990) Ratio of flow depth to grain size; step-pool

cascade; pool-riffle; meandering/braided

Frissell (1982) Origin of the nested habitat hierarchy

approach from micro-habitat, through meso-

scale to stream system

Nanson and Cloke (1992) Classification of floodplains in to 3 class

system: High-energy non-cohesive;

medium-energy non-cohesive and low-

energy cohesive; 13 derivative orders and

sub-orders.

THE APPLICATIONS/FIELD

SURVEY PHASE

(1990-2005)

River Corridor Survey (NRA, 1992) UK mapping protocol of river habitats at 500m scale

River Styles (Brierley et al. 2003,) 9 River geomorphic river types; Australia

Rosgen River Classification (1994) 20 basic geomorphic river types and sub-divisions;USA

River Habitat Survey (Raven et al,

1997)

Field based physical habitat mapping at 500m scale and

calculation of habitat quality and modification scores

Montgomery and Buffington (1997) 9 fold process based geomorphic classification derived form

observations ain the Pacific North West, USA.

Fluvial audits (Sear et al. 1995) Systematic approach to recording river geomorphology to relate

channel condition and stability to sediment transport processes

SERCON (Boon et al., 1998 System for evaluating River Conservation. Includes habitat

diversity

Graham et al. (2005) Digital photogrammetry software for sizing bed material classes.

MDBC (2008) Sustainable rivers audit (2004-7) Murray Darling Basin

Authority

GEORHS (Branson et al. 2005) A refined geomorphological and floodplain component of RHS

MiMAS (SNIFFER, 2005 Impact assessment tool based on river typing and professional

judgement

Rosgen, 1994

Broad chanel type descriotion Bedrock

Plane bed/

Step pool

Pool riffle ,

Wandering etc Active meandering Chalk

Passive meandering

eg carse/clay

Channel type Type A Type B Type C Type D Type E Type F

Activity Footprints (m)

Sediment Removal 0 0 0 0 0 0

Sediment Manipulation 0 0 0 0 0 0

Dredging 0 0 0 0 0 0

Riparian Vegetation Loss 0 0 0 0 0 0

Embankment 0 0 0 0 0 0

Set Back Embankment 0 0 0 0 0 0

Hard Bank Protection 0 0 0 0 0 0

Soft Bank Protection 0 0 0 0 0 0

Bank Reprofiling 0 0 0 0 0 0

Straightening 0 0 0 0 0 0

Realignment Partly Recovered 5- 0 0 0 0 0

Flood Bypass 0 0 0 0 0 0

Culverts 0 0 0 0 0 0

Croys/Flow Deflectors 0 0 0 0 0 0

Bed Reinforcement 0 0 0 0 0 0

Weirs 0 0 0 0 0 0

Artifical Substrate 0 0 0 0 0 0

Bridge Piers 0 0 0 0 0 0

Hydro Regime EXT Modified 0 0 0 0 0 0

Sediment Regime EXT Modified 0 0 0 0 0 0

Channel #VALUE! #VALUE! 0.0% HIGH 0.0% HIGH 0.0% HIGH 0.0% HIGH 0.0%

Banks and Riparian zone vegetation #VALUE! #VALUE! 0.0% HIGH 0.0% HIGH 0.0% HIGH 0.0% HIGH 0.0%

Flow #VALUE! #VALUE! 0.0% HIGH 0.0% HIGH 0.0% HIGH 0.0% HIGH 0.0%

Floodplain zones #VALUE! #VALUE! 0.0% HIGH 0.0% HIGH 0.0% HIGH 0.0% HIGH 0.0%

Longitudinal continuity #VALUE! #VALUE! 0.0% HIGH 0.0% HIGH 0.0% HIGH 0.0% HIGH 0.0%

MiMAS, Greig, S.M., Richardson, R.

and Gibson, J. (2006)

ADVANCES IN RIVER SCIENCE AND

DIGITAL DATA PHASE

(>2005)

Huryn et al., 2005 River typing and arctic stream communities

Fluvial Information System (Dugdale and

Carbonneau, 2009)

Remote sensing system for mapping

instream physical habitat

Harvey et al (2006) Classification of flow biotypes

Harris et al. (2009) Multivariate geomorphological river

typing; Australia

Fonstad and Marcus (2010) Mapping river systems as basin wide extent

using remote sensing as an aid to

understanding.

Schmidt et al., (2007) A quantitative morphodynamic typology on

the upper Rhine.

Milner (2010) Multivariate geomorphological and

ecological river typing; data obtained at 20

times channel width

Bowden-Smith And Gilvear (in prep) Google earth

Parker et al. (In press) Use of stream power to determine sediment

transport of bed material

Terrestrial LiDAR; image of

woody debris on gravel bar;

courtesy of James Brassington

Googleearth and RHS

scores

Figure courtesy of Fiona

Thompson; data provided by

Richard Jefferies, SEPA

Stream power on

the River Spey

channel networkSpecific Stream Power along

River Spey Medium Scenario by

2080 Stream type;

simplified

Mongomery and

Buffington

Figure courtesy of Fiona

Thompson; data provided by

Richard Jefferies, SEPA

Figure courtesy of Fiona

Thompson; data provided by

Richard Jefferies, SEPA

CASE STUDIES FROM THE RIVER SCIENCE

PHASE

River reconnaissance and the Scottish Beaver

Trial (Gilvear and Casas-Mulet, 2010)

Bespoke Geomorphic assessment

Two ‘Wolman’ pebble counts

At 50 metre intervals• Upstream/downstream photograph

• Channel dimensions

• Riparian woodland width, density (isolated-continuous) and structure

• Fallen trees (within 25m; length categories)

• Instream woody debris (twig- branch and location full width/marginal)

• Wetlands and ponds

• Salmonid hydraulic habitat (six types –riffle – cascade)

• Erosion-deposition feature

River reconnaissance and appraisal on the

Faeshallach Burn for restoration options

(Gilvear and Perfect, 2010)

Reach-scale river typing on the River Dee

(Milner, 2010)

Ward-linkage dendrogram (HCA) of reaches using an indicator of water depth,

discharge, grain size and velocity

Physical habitat variables in PCA space. Channel types are ○ step-pool,

plane-boulder bed, ◊ plane-gravel bed, ▌bedrock, active meandering, and

■ passive meandering.

TWINSPAN classification of 43 minimally impacted study reaches based

on macro-invertebrate family abundance data. Numbers in bold designate

a group’s number and numbers in brackets indicated the number of study

reaches in that group.

FUTURE CHALLENGES: SCALE AND

HETEROGENEITY

River and channel width Number of channel widths per

500 metres

Survey reach length for 20 times

channel width

UK

Forth at Stirling (85m) 5.9 1700m

Tay at Dunkeld (129m) 3.9 2580m

Wye at Chester (84m) 5.9 1700m

Thames at Oxford (54m) 9.3 1080m

Spey at Fochabers (105m) 4.7 2010m

Clyde at Glasgow (51m) 9.8 1020m

Worldwide

Ganges at Danapur (1400m) 0.35 28,000m

Nile at Asyat (803m) 0.62 16,060m

Danube at Belgrade (781m) 0.64 15620m

Amazon at Manaus (4100m) 0.12 82000m

Brahmaputra at Dibrugah (10.5km) 0.05 210,000m

Yukon at Circle Hot Springs

(4100m)

0.12 82000m

Scale

Need to turn to downstream hydraulic geometry for

the answer

Using the Montgomery and Gran (2001) hydraulic

geometry relationship for Stasop River in Pacific

North West of States

Survey lengths at twenty channel widths would be

60m, 147m, 480m, 875m, 1640m at catchment

areas of 1km2, 25km2, 100km2, and 250km2

respectively.

Surveying at appropriate scales

Multiple scales – going beyond meso-habitat mapping

Baxter and Hauer (2000) have shown of redds of the

fall-spawning bull charr (Salvelinus confluentus) is

centred on low-gradient alluvial valley segments which

has regional upwelling creating the thermal conditions

conducive to egg incubation but that local siting is in

well oxygenated downwelling water.

Only multi-scalar analysis could reveal this relationship

between pattern and process.

The challenge is to integrate gradients, reaches, and

patches.

Embrace heterogeneity

•Heterogenity is likely to be a measure of stream health but

at what scale?

•As Fausch et al., (2002) state “the gap we must bridge is at

an intermediate scale in both space and time. Biologists

have always sampled at the small scale even when over

basin extents”.

•Jahnig et al. (2010) suggests that place centred restoration

for macroinvertebrates has not worked due to it focussing on

the micro and meso-scale.

The key is to understand where differing levels of

heterogeneity and homogeneity impinge on river ecosystem

function and at what scale and then measure appropriately.

Channel X-section

heterogeneity on the

River Namoi,

Australia

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Riverscape heterogeneity (Dimensionless variables)

Catchment scale river network Histogram of stream order frequency

Abundance, evenness and richness of river types

2D reach scale planform Number of geomorphic features and landscape ecology indicators (e.g Shannon

Weiner)

Channel width variability

2D reach scale channel cross-

sectional variability

Statistics describing variability in channel width-depth ratio, channel asymmetry

Statistics describing variability in wetted perimeter to semi-circular cross-

sectional wetted perimeter

2D at-a-site channel cross-section

morphology

Measured wetted perimeter to semi-circular cross-sectional wetted perimeter

2D at-a-site channel cross-section

flow hydraulics

Statistics describing variability in cross channel flow velocities and other

parameters (e.g. Froude number)

2D at-a-site channel substrate Statistics describing variability in D50 and other indictors of particle size

1D at-a-site vertical cross-

channel flow hydraulics

Statistics describing variability in surface flow velocities

1D at-a-site downstream

changes in flow hydraulics

Statistics describing variability in surface flow velocities

1D bed material Descriptors of bed material particle size distribution

CONCLUSION

•Catchment appraisal, river typing and reconnaissance is now

mainstream and truly integrated in to river management.

•Despite the complexity of river systems approaches and methodologies

have been developed that cope with the challenge of fluvial systems

•The emergence of river science as a discipline has provided an solid

foundation for understanding eco-geomorphological and hydro-

geomorphological processes.

•Need to me more sophisticated and clever in our appraisals to maximise

the new armoury of weapons we have at our disposal. Potential for new

insights in to theoretical understanding

•A greater focus on the implications of scale of analysis and

measurement of heterogeneity at multiple scales.