The role of water markets in climate change adaptation

Abstract Water markets were first introduced in Australia in the 1980s, and water entitlement and allocation trade have been increasingly adopted by both private individuals and government.Irrigators turned to water markets (particularly for allocation water) to manage water scarcity and Governments to acquire water for the environment (particularly water entitlements. It is expected that further adoption of water markets will be essential for coping with future climate change impacts. This report reviews the available literature related to the relationship between southern Murray-Darling Basin (sMDB) water markets and anticipated climate change effects; the economic, social and environmental impacts of water reallocation through markets; and future development requirements to enhance positive outcomes in these areas. The use of water markets by irrigators can involve both transformational (selling all water entitlements and relocating or switching to dryland) and incremental (e.g. buying water allocations/entitlements, using carry-over, changing water management techniques) adaptation to climate change. Barriers to both adaptations include: current and future climate uncertainty; poor (or non-existent) market signals; financial constraints; information barriers; mental processing limits; inherent attitudes toward or beliefs about climate change; institutional barriers and disincentives to adapt. A better understanding of trade behaviour, especially strategic trade issues that can lead to market failures, will improve the economic advantages of water trade. There remains community concerns about the impacts of transfers away from regional areas such as reduced community spending and reinvestment; population losses; loss of jobs; declining taxation base, loss of local services and businesses, regional production changes; and legacy issues for remaining farmers. However, it is hard to disentangle these impacts from those caused by ongoing structural change in agriculture. Rural communities that are most vulnerable to water scarcity under climate change and water trade adjustment include smaller irrigation-dependent towns. Communities less dependent on irrigation are better able to adapt. Further, where environmental managers use water markets to deal with water variability and to ensure ecological benefits, irrigators are concerned about its impact on their traditional use of markets to manage scarcity. Climate change and water scarcity management are intertwined, suggesting that policy, institutional and governance arrangements to deal with such issues should be similarly structured. Water users will adapt, either out of necessity or opportunity. The cost of that adaptation at individual, regional and national levels—particularly to future water supply variability—can be mitigated by the consideration of the existing advantages from future opportunities for water marketing in Australia

Distribution of heavy metals in vegetative biofiltration columns

This study investigated the distribution of heavy metals in vegetative biofiltration columns irrigated by synthetic greywater. Twelve species of ornamental plants (three plants from each species) were planted in the same designed 36 biofiltration columns. Samples of effluent water, soils, roots, shoots and leaves were collected and analyzed. It was observed that before irrigation, the distribution of copper was in soils (0%), roots (42%), leaves (37%) and shoots (21%). After irrigation, this distribution changed to soils (29%), roots (39%), leaves (17%) and shoots (15%). It was found that lead concentrations decreased in soils from (84% to 7%), but increased in plants (from 16% to 93%) following irrigation with greywater. In contrast, the distribution of zinc changed from leaves (46%), roots (22%) and soils (16%) before irrigation to 89% in leaves and soils and 11% in shoots following irrigation. The chromium distribution before and after irrigation was found to be almost unchanged in soils, shoots and effluent water, but it increased in roots (19.4% to 26.9%) and decreased in leaves (11.4% to 5.8%). The outcomes of this study demonstrated that heavy metals mostly accumulate in soils and roots, and it is necessary to investigate their potential detrimental effects on the receiving environment

An assessment of the drainage quality and quantity associated with recycled wastewater irrigation in an urban park

8 p.International audienceQuantification of drainage to remove excess water from the soil profile and provide a suitable environment for vegetation has been developed over the years. Drainage estimation is fairly challenging particularly in the heterogeneous urban environs. This research studied the temporal variation of drainage rate and nutrient leaching in Veale Gardens of Adelaide Parklands, Australia. A zero tension pan lysimeter was installed in an urban mixed vegetation park to study the quantity and quality of leachate solute. EM38 soil mapping and spatial analysis allowed mapping of two EC zones. Temporal changes of volume and characteristics of drained water were studied in the low EC zone for two seasons of summer and winter. The outcomes showed that the volume of drained water in the summer time was considerably less than in the winter time. This is likely to be the cause of the winter dormancy in most plants and evapotranspiration reduction in winter time. Chemical analyses of leachate solute showed a significant drop in the values of EC, potassium, total N, total P, and ionic balance from summer to winter despite a large increase in SAR. In terms of nutrient loading during the study period, this work has shown that there would be very little impact from using recycled waste water compared to conventional water sources

Local infrastructure in Australian tourist destinations: modelling tourism demand and estimating casts of water provisions and operation

With so many tourist activities in Australia, consideration must be given to the impact of the tourist on the environments in which they are located. Sustainable practices and in particular those associated with water use and wastewater production are important in planning for current tourist activity and future growth of visitors in urban and rural areas. The objectives of this research include an investigation and review of the options available to provide, operate and fund water and wastewater infrastructure to meet growing tourism needs in a sustainable manner. This has led to the development of a modelling framework for facilitating a range of analysis related to water use at Australian tourism destinations. The adopted modelling methodology includes procedures for estimating base year and forecasted tourist population at the tourist destination, water and wastewater demands associated with the visitor population, infrastructure required to satisfy water demands at the tourism region and the cost of such infrastructure provisions. This is achieved by incorporating tourist and residential population estimation for a base year and for a series of forecast future years. Population estimations are based on current and available survey data including regional tourism surveys, international and national visitor surveys and Australian census data. Water and wastewater requirements for these combined populations at the tourist destination are calculated with inclusions for irrigation based on CROPWAT software outputs. The corresponding costs of water provision and wastewater collection can then be summarised, based on the preceding estimations. To allow for application to all Australian tourism localities, the modelling process is adapted to suit data that is readily available or easily collected and involves principles that can be readily applied by the user. This methodology outlines some urban water use and wastewater production statistics across Australian capital cities, useful in later calculations. Case study applications of the model are developed for the Australian tourist destinations of Daylesford in Victoria and Byron Bay in New South Wales. Analysis includes full calculations for the water and wastewater needs and associated costs for the forecast year of 2031. Some key findings from the analysis are that for the year 2031, the costs associated with Daylesford’s residential and tourist population demand will be $32,289,650 for the total water demand and$11,128,000 for wastewater treatment. For the town of Byron Bay in 2031, these costs will be $53,601,500 for the total water demand and$18,644,000 for wastewater treatment. Major benefits of this research include better knowledge and understanding of tourist demands, and the need for water and wastewater infrastructure and analytical tools, enabling councils and other authorities to quantify present and future tourist demands, infrastructure requirements to meet demand, and the associated costs of infrastructure provision and operation

Selecting an appropriate size for domestic rainwater tanks in Colombo

Both India and Sri Lanka have experienced rapid population growth and migration to the major cities in the past decade. This rapid urbanisation has resulted in overstressing of existing water supply systems, with a loss of recharge areas and an increased depletion of groundwater. These effects have further aggravated the urban water crisis. During the monsoons, the existing drainage systems are overloaded and overflow thereby resulting in flooding causing severe damage to property. Sewage overflows often lead to the outbreak of epidemics and occasionally to the loss of life. Rainwater harvesting systems serve the dual purpose of water storage to reduce urban runoff peak flows as well as augmentation of the existing water supply systems. To achieve minimum costs while optimising the security of supply, rainwater tanks need to be sized taking the local rainfall conditions into consideration. This paper presents a methodology to determine the optimal size of rooftop storage based on historical rainfall data. Annual savings of in-house demand as well as the security of rainwater supply are discussed. The methodology is applied to Colombo in Sri Lanka. A case study is based on 150lpd household demand with 25m2 of roof area in Colombo. The appropriate rainwater tank is determined to be 2000 L in capacity. The resulting water saving is 54% of annual in-house demand and more importantly, zero supply from the tank happens during only one third of the year

The Influence of Plant Type, Substrate and Irrigation Regime on Living Wall Performance in a Semi-Arid Climate

Living walls are fast becoming a ubiquitous feature of modern living and are widely implemented in commercial buildings in both internal and external environments. However, there are several challenges associated with maintaining healthy plant growth on these water sensitive urban design systems. This experimental study of an instrumented prototype-scale living wall has found that there is a close relationship between the plants, substrates and adopted irrigation regimes. In this study, plant selection was found to be more critical than either substrate or irrigation regime selection. This research also found that both the location of the plants on the wall and irrigation volume significantly affected the plants’ ultimate total dry weight. In particular, plants were found to grow taller on the upper section of the living wall compared to the middle and lower sections. It is recommended that particular attention should be given to plant location and the amount of irrigation water supplied at different positions on the living wall

The Role of Green Roofs and Living Walls as WSUD Approaches in a Dry Climate

The addition of green infrastructure, including green roofs and living walls, into buildings is part of a new approach to urban design aimed at resolving current problems associated with built environments. Green roofs and living walls are becoming an important component of water sensitive urban design systems, and their use around the world has increased in recent years. Green roofs can cover the impermeable roof areas that densely populate our urban areas, and through doing so, can provide many environmental, economic, and social benefits. In addition to roofs, there are a number of bare walls that have the potential to be transformed into vegetated, living walls. Living walls can potentially improve air quality, reduce pollution levels, reduce temperatures inside and outside of buildings, reduce building energy usage, and improve human health. Despite such benefits, both green roofs and living walls are relatively new technologies, and there are several research gaps and practical barriers to overcome before these systems can be applied more widely. Furthermore, specific design criteria need to be developed for a range of climatic conditions to develop resilient green infrastructure. Consequently, several field experiments comprising both intensive and extensive green roof test beds, as well as living walls, have been recently established. In these recent research studies, stormwater quality and quantity, hydrological behavior, plant performance, and thermal benefit have been investigated. The findings of these studies can be used to identify the key elements of resilient green roof and living wall systems

The Role of Green Roofs and Living Walls as WSUD Approaches in a Dry Climate

The addition of green infrastructure, including green roofs and living walls, into buildings is part of a new approach to urban design aimed at resolving current problems associated with built environments. Green roofs and living walls are becoming an important component of water sensitive urban design systems, and their use around the world has increased in recent years. Green roofs can cover the impermeable roof areas that densely populate our urban areas, and through doing so, can provide many environmental, economic, and social benefits. In addition to roofs, there are a number of bare walls that have the potential to be transformed into vegetated, living walls. Living walls can potentially improve air quality, reduce pollution levels, reduce temperatures inside and outside of buildings, reduce building energy usage, and improve human health. Despite such benefits, both green roofs and living walls are relatively new technologies, and there are several research gaps and practical barriers to overcome before these systems can be applied more widely. Furthermore, specific design criteria need to be developed for a range of climatic conditions to develop resilient green infrastructure. Consequently, several field experiments comprising both intensive and extensive green roof test beds, as well as living walls, have been recently established. In these recent research studies, stormwater quality and quantity, hydrological behavior, plant performance, and thermal benefit have been investigated. The findings of these studies can be used to identify the key elements of resilient green roof and living wall systems

Distribution Of Hydrological Losses For Varying Rainfall And Antecedent Wetness Conditions

Hydrological loss is a vital component in many hydrological models, which are usedin forecasting floods and evaluating water resources for both surface and subsurface flows. Due to the complex and random nature of the rainfall runoff process, hydrological losses are not yet fully understood. Consequently, practitioners often use representative values of the losses for design applications such as rainfall-runoff modelling which has led to inaccurate quantification of water quantities in the resulting applications. The existing hydrological loss models must be revisited and modellers should be encouraged to utilise other available data sets. This study is based on three unregulated catchments situated in Mt. Lofty Ranges of South Australia (SA). The paper focuses on conceptual models for: initial loss (IL), continuing loss (CL) and proportional loss (PL) with rainfall characteristics (total rainfall (TR) and storm duration (D)), and antecedent wetness (AW) conditions. The paper introduces two methods that can be implemented to estimate IL as a function of TR, D and AW. The IL distribution patterns and parameters for the study catchments are determined using multivariate analysis and descriptive statistics. The possibility of generalising the methods and the limitations of this are also discussed. This study will yield improvements to existing loss models and will encourage practitioners to utilise multiple data sets to estimate losses, instead of using hypothetical or representative values to generalise real situations

A Statistically Rigorous Approach to Experimental Design of Vertical Living Walls for Green Buildings

Living walls (LW) have been widely proposed as a form of green infrastructure to improve aesthetics, energy consumption, and microclimate in urban environments by adding densely-planted vegetation to the outside walls of buildings. Scientific studies using multiple treatments in a single LW face challenges due to the close physical proximity of different treatments, particularly the potential for plants above to influence those below. A study on a west-facing LW was undertaken to investigate 36 unique treatments in Adelaide, South Australia, for nine months. The LW comprised combinations of six native plant species, three soil substrates and two irrigation volumes. The LW consisted of 144 modular trays mounted on a wall in a 12 × 12 grid with four replicates of each treatment. The location of each treatment was designed to account for a cascading carry-over effect that may be present when one plant is placed above another. Carry-over effect of the model designed showed mixed results among the plant groups identified. It was also found that long-form plants can significantly shade smaller plants below them. Experimental research into the performance of plants in mixed species LW should consider the carry-over effect to account for this