An integrated modelling approach for assessing water policy rules and land use change options

The primary aim of the study has been to develop a modelling framework to quantitatively assess the impact of water allocation rules upon economic and biophysical environments (primarily hydrological) at the catchment scale. This paper identifies development of the modelling approach to answer allocation questions by examining hydrological, land and agricultural production systems. The conceptual framework underpinning the modelling approach identifies the major aspects of integration between hydrological and production systems. The production model is integrated at various points within the hydrological cycle including rainfall, streamflow and runoff components. The outcome of the approach allows water to be moved around the catchment to quantify impacts and understand trade-offs as a result of policy imposition and land use change. The results indicate the land use change for salinity management has the potential to impact upon intensive activities within the catchment such as viticulture

Experiences in an integrated assessment of water allocation issues in the Namoi river catchment, Australia

The Namoi river catchment in northern NSW is an important irrigation region. However water resources in this region are increasingly stressed. Both surface and groundwater supplies are overallocated in many areas of the catchment. Management options to reduce allocations in line with available supply and environmental requirements are expected to have long term social, economic and environmental implications. This paper looks at an integrated assessment model which has been developed to assess long term outcomes of management options for water allocation in the catchment. The development of this tool has been undertaken using an iterative approach with key stakeholders. Feedback on the model and preferred future directions of development arising from discussions with relevant stakeholder groups are discussed. A key aspect of the model framework is that it has been developed to be general enough for reapplication to water allocation issues in other catchments Lessons are drawn from this experience in framework development for the field of integrated assessment

Integrated Water Resources Assessment and Management (IWRAM) Project: Integrated Toolbox

The integrated toolbox of the IWRAM Decision Support System links household scale socio-economic models with a biophysical modelling toolbox (Merritt et al., 2001). In the biophysical toolbox, land use decisions are "painted" onto the catchment by the user. By contrast, the integrated toolbox simulates land use decisions by using models of household decision making. This allows the user to investigate the social and economic constraints on land and water use, and to look at the impacts of climate, prices and management policies on households. The impact of household decisions on a range of biophysical indicators is able to be demonstrated and trade-offs between upstream and downstream users of water are also able to be investigated

Lean interfaces for integrated catchment management models: rapid development using ICMS

A move towards the development of lean, issue-focused interfaces is being explored to provide a rapid delivery mechanism to transfer catchment science to managers and custodians. This approach is a move away from development of large decision support systems which attempt to anticipate a myriad of management questions. It relies on having a modelling system which supports the rapid building and integration of catchment models, and is independent of the interface. ICMS (Interactive Component Modelling System) is a PC-based software tool which has been developed with this in mind. The kernel of the ICMS system, ICMSBuilder, provides the modeller’s view of the world, on top of which can be built any number of interfaces which provide the targetted audience’s view of the world. This paper presents an ICMS prototype to demonstrate the power and flexibility of such an approach. It describes an ICMS project - a suite of linked models which explore the relationships between hydrology, water allocation and extraction rules, and on-farm decision making; and an ICMS View - an interface for that project tailored to address specific management scenarios. Interestingly, the ability to interact with parts of the models through the View gave managers the confidence to delve into the underlying models and data, something often denied to them by traditional decision support systems

Forward projection of transient signals obtained from a fiber-optic pressure sensor

An analytical/experimental approach is presented to reconstruct the space–time pressure field in a plane and forward project the resultant space–time pressure field using tomographic and wave vector time-domain methods. Transient pressure signals from an underwater ultrasonic planar transducer are first measured using a line fiber-optic pressure sensor which is scanned across a plane at a fixed distance z0 from the transducer. The resulting spatial line integrals in the plane are time-dependent signals which are first used to reconstruct the space–time pressure field in the plane via simply implemented tomographic methods. These signals are then used to forward project the space–time pressure field to arbitrary planes employing a wave vector time-domain method. Verification of the method is first presented using synthetic signals and the impulse response approach. An experimental verification of the approach is then presented using an ultrasonic planar transducer. The results of the projected and experimental fields are compared at various distances for synthetic signals and experimental data. Good correlation is found between the calculated, projected, and experimental data

Increasing Liana Abundance and Basal Area in a Tropical Forest: The Contribution of Long‐distance Clonal Colonization

Recent evidence suggests that liana abundance and biomass are increasing in Neotropical forests, representing a major structural change to tropical ecosystems. Explanations for these increases, however, remain largely untested. Over an 8‐yr period (1999–2007), we censused lianas in nine, 24 × 36 m permanent plots in old‐growth and selectively logged forest at La Selva Biological Station, Costa Rica to test whether: (1) liana abundance and basal area are increasing in this forest; (2) the increase is being driven by increased recruitment, decreased mortality, or both; and (3) long‐distance clonal colonization explains the increase in liana abundance and basal area. We defined long‐distance clonal colonization as lianas that entered and rooted in the plots as vegetative propagules of stems that originated from outside or above the plot, and were present in 2007, but not in 1999 or 2002. Our hypotheses were supported in the old‐growth forest: mean liana abundance and BA (≥1 cm diameter) increased 15 and 20 percent, respectively, and clonal colonization from outside of the plots contributed 19 and 60 percent (respectively) to these increases. Lianas colonized clonally by falling vertically from the forest canopy above or growing horizontally along the forest floor and re‐rooting—common forms of colonization for many liana species. In the selectively logged forest, liana abundance and BA did not change, and thus the pattern of increasing lianas may be restricted to old‐growth forests. In summary, our data support the hypothesis that lianas are increasing in old‐growth forests, and that long‐distance clonal colonization is a major contributor