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4 Stage Four, Step Three: Prioritize efforts based on geomorphic condition and recovery potential

4 Stage Four, Step Three: Prioritize efforts based on geomorphic condition and recovery potential

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Chapter 12



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Figure 12.4 Target conditions for the channelized fill River Style in Bega catchment (from Fryirs, 2001)

Reaches in different geomorphic condition are used to determine target conditions for river rehabilitation. Those

reaches in good and moderate condition are used to determine the geomorphic structure and vegetation associations

required for river rehabilitation along reaches in poor condition. In this example the channelized fill River Style is

presented.



orous manner without catchment-framed baseline

surveys and a catchment-vision. A prioritization

framework determines the sequencing of actions

that can be applied to achieve the catchment-based

vision. Defining what is achievable in big-picture

terms allows prioritization frameworks for river

conservation and rehabilitation programs to be effectively applied. These prioritization frameworks

ensure that the most cost-effective and efficient

reach based strategies work towards the catchment vision.

While economic, cultural, and social values

place obvious constraints on application of prioritization frameworks, a physical template forms a

critical basis for decision-making. By applying a

physical prioritization framework, reaches where

the greatest likelihood of success is likely to be attained are identified. In many cases, the rehabilitation of strategic reaches triggers positive responses



elsewhere, enhancing prospects for recovery

throughout the catchment.

The prioritization procedure applied in the River

Styles framework is presented in Figure 12.7.

Particular emphasis is placed on “unique” attributes of a catchment (e.g., rare types of river), regardless of their condition, and those rivers that

remain intact (i.e., remnants of predisturbance

conditions). These reaches form the basis from

which to work outwards into more degraded sites

in the catchment. Emphasis is then placed on

strategic reaches that protect conservation priorities, and reaches that have high recovery potential.

Finally, more difficult tasks are contemplated, in

the most degraded parts of the catchment.

The philosophical perspective that underpins

the prioritization strategy for management efforts

in the River Styles framework is as follows

(Brierley and Fryirs, 2000):



Stage Four of the Rivers Styles framework



351



Figure 12.5 Target conditions for the partly-confined valley with bedrock-controlled discontinuous floodplain pockets

River Style in Bega catchment (from Fryirs, 2001)

Reaches in different geomorphic condition are used to determine target conditions for river rehabilitation. Those

reaches in good condition are used to determine the geomorphic structure and vegetation associations required for

river improvement. In this example the partly-confined valley with bedrock-controlled discontinuous floodplain

pockets River Style is presented, showing how reaches in moderate geomorphic condition are initially used as a target

condition for reaches in poor condition. Once the moderate condition is attained, reaches in good condition provide

the ideal target condition for further rehabilitation.



1 Conservation precedes rehabilitation. Since

habitat conservation is the key to maintaining the

biodiversity of aquatic ecosystems, preservation of

remaining near-intact fragments of river courses is

the first priority. Refugia must be retained under

differing flow conditions (e.g., ensuring that pools

continue to support water under low flow conditions). Inevitably, the distribution of conservation

reaches is fragmented. Most “near-intact” reaches

are in national parks in relatively inaccessible

parts of the landscape. Given their isolation, these

remnants are often unrepresentative of predisturbance conditions in a wider context. However, the

systematic, but inadvertent, destruction of former

ecological attributes of river courses makes these

remnants all the more precious in terms of their



conservation and heritage values. Hence, putting

aside the protection of infrastructure and equivalent site-specific requirements, emphasis is placed

on conservation of reaches that have unique geomorphic structure, or are remnants of predisturbance conditions.

2 Strategic reaches with potentially threatening

off-site impacts are the second priority. Particular

attention is given to reach or point-impacts that

threaten conservation reaches. Irrespective of

their geomorphic condition, these reaches must be

targeted early in the river rehabilitation process. In

many cases, the effects of rehabilitation of strategic reaches will be propagated throughout a

catchment, enhancing the natural recovery of adjoining reaches. Identification of strategic reaches



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Figure 12.6 Target conditions for the low sinuosity sand-bed River Style in Bega catchment (from Fryirs, 2001)

Reaches in different geomorphic condition are used to determine target conditions for river rehabilitation. Those

reaches in good and moderate condition are used as target conditions for river rehabilitation programs that tackle

reaches in poor condition. These target conditions provide a basis to identify the geomorphic structure and vegetation

associations required for river improvement. In this example the low sinuosity sand bed River Style is presented.



shifts the emphasis of river rehabilitation practice

from reactive to proactive decision-making.

Preemptive management strategies target reaches

that are adjusting “unnaturally” or show signs of

accelerated or anomalous behavior yet retain inherent ecosystem values. These reaches have the

greatest potential to change, impacting negatively

in terms of loss of values and associated off-site impacts. Within this category, infrastructure/asset

protection and mitigation of negative societal impacts are also considered as priorities.

3 The next strategy is to work in reaches with high

natural recovery potential, thereby maximizing

the likelihood of management success. Whenever

possible, the ideal sites to commence rehabilitation programs are connected to those parts of the

catchment in which river character and behavior



are in good condition (e.g., high conservation value

reaches), such that longer-term strategies can

build on greater lengths of river which have appropriate river structures for their setting. Isolated

reaches with high recovery potential may provide

important foci or starting points for river rehabilitation. In this way, the longitudinal connectivity

of reaches in good geomorphic condition is maximized. Less impacted sections of a River Style are

used to assess appropriate target conditions for

more degraded river reaches of the same River

Style. Strategies that mimic the character and behavior of good condition reaches of the particular

River Style will be most cost-effective in the long

term, and will require minimal on-going maintenance. As recovery is already underway, a “donothing” option may be quite feasible in these



Stage Four of the Rivers Styles framework



353



Figure 12.7 Prioritization of river

reaches based on their geomorphic

condition and recovery potential



reaches. Elsewhere, minimally invasive approaches based on riparian vegetation management may

facilitate accelerated recovery.

4 Consider more difficult tasks. In degraded

reaches that are experiencing sustained adjustment, costly river rehabilitation programs may not

yield substantive outcomes, adversely impacting

on community confidence in the river management process. Ultimately, this may prolong or

compromise the achievement of the vision.

Degraded reaches often require invasive rehabilitation techniques with costly on-going maintenance. Although conventional river engineering

practices can be employed, the most cost-effective

strategy may simply be to wait for these reaches to

regain some sort of physical balance before adoption of intervention strategies. In many cases,

management success along these reaches will only

be attainable at reasonable cost once rehabilitation

has been achieved in upstream reaches. Over time,

cumulative, off-site improvement may aid the recovery of low recovery potential reaches. Hence,

framing goals in context of the catchment vision

aids the prospects for rehabilitation success

throughout the system.



Application of the River Styles prioritization

procedure in working towards the catchmentbased vision for Bega catchment is presented in

Plate 12.1.



12.5 Stage Four, Step Four: Monitor and audit

improvement in geomorphic river condition

Effective monitoring of river rehabilitation programs is a prerequisite for appraisal of successes

and failures. Unfortunately, such endeavors have

largely been overlooked in the past. This oversight

reflects, in part, the short-term nature of many rehabilitation projects and associated funding, a lack

of “requirement” to undertake monitoring, limited baseline information against which to monitor

change, and poor articulation of objectives of what

to monitor and why (Kondolf, 1995; Kondolf and

Micheli, 1995). Underlying these factors is a lack of

a clearly specified vision and measurable objectives. Procedures for monitoring and auditing

must be considered at the outset of any program.

Postproject appraisals that endeavor to learn from

experience must be tied to preproject data (Downs



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and Kondolf, 2002). Adoption of adaptive management principles, whereby clearly definable and

realistic goals are regularly reappraised and readjusted, optimizes the likely success of monitoring

programs, aiding the reinforcement of ideas and

learning.

Stratification of landscapes into areas dominated by similar processes aids the design and implementation of effective assessment and monitoring

strategies (Montgomery, 1999, 2001). If stratified

too finely, local dynamics are hard to interpret because they are driven largely by external processes.

If landscape stratification is too coarse, it may be

difficult to delineate causal linkages. Hence, the

spatial scale at which a monitoring program is applied strongly influences its usefulness for ecosystem management. Data must be framed in context

of the disturbance history, evolutionary tendency,

and linkages of biophysical processes that operate

in the system of concern.

The River Styles framework provides a multiscalar, process-based procedure by which monitoring programs can be structured in a manner that

relates to the “natural” range of diversity evident

along a river course, comparing like with like

in a meaningful manner (see Boulton, 1999).

Catchment-wide River Styles maps can be used to

select representative sampling points, reflecting

inherent variability in river character and behavior, and measures of geomorphic river condition.

Sampling strategies can then target relevant geoecological attributes of different types of rivers,

reflecting the array of differing landforms, vegeta-



tion associations, and hydraulic diversity evident

in these different settings.

If issues of monitoring and auditing are to be addressed in a comprehensive manner, an inventory

of river diversity and condition at State and/or

National levels is required. Without this inventory, the uniqueness or rarity of different types of

river character and behavior cannot be determined. Various structural and practical constraints have inhibited the development of truly

integrative biomonitoring programs (Armitage

and Cannan, 1998).



12.6 Products of Stage Four of the River

Styles framework

Products derived from Stage Four of the River

Styles framework include:

• tables outlining the catchment-based vision and

plan of attack;

• photographs and tables demonstrating target

conditions and actions required to move a reach

along the recovery trajectory and improve its

condition;

• catchment-based prioritization map, with boxes

that demonstrate the actions that will be taken to

enhance the recovery of representative and strategic reaches and achieve the catchment vision;

• a geomorphic platform upon which representative auditing procedures can be developed and

applied.



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