Planning for "water-sensitive" cities has become a priority for sustainable urban development in Australia. There has been little quantification of the term, however. Furthermore, the water balance of most cities is not well known. Following prolonged drought, there has also been a growing need to make Australian cities more water self-reliant: to source water from within. This article formalizes a systematic mass-balance framework to quantify all anthropogenic and natural flows into and out of the urban environment. Quantitative performance indicators are derived, including (1) degree of system centralization;(2) overall balance; potential of (3) rainfall, (4) stormwater, and (5) wastewater to offset current demand; and (6) water cycle rate. Using the method, we evaluate Sydney, Melbourne, South East Queensland and Perth using reported and modeled data. The approach makes visible large flows of water that have previously been unaccounted and ignored. It also highlights significant intercity variation. In 2004-2005, the cities varied 54% to 100% in their supply centralization, 257% to 397% in the ratio of rainfall and water use, 47% to 104% in their potential stormwater recycling potential, and 26% to 86% in wastewater recycling potential. The approach provides a practical, water-focused application of the urban metabolism framework. It demonstrates how the principles of mass balance can help foster robust water accounting, monitoring, and management. More important, it contributes to the design and quantitative assessment of water-sensitive cities of the future.

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A decline in the ecosystem health of Australia's Moreton Bay, a Ramsar wetland of international significance, has been attributed to sediments and nutrients derived from catchment sources. To address this decline the regional management plan has set the target of reducing the loads by 50%. Reforestation of the channel network has been proposed as the means to achieve this reduction, but the extent of revegetation required is uncertain. Here we test the hypothesis that sediment and nutrient loads from catchments decrease proportionally with the increasing proportion of the stream length draining remnant vegetation. As part of a routine regional water quality monitoring program sediment and nutrient loads were measured in 186 flow events across 22 sub-catchments with different proportions of remnant woodland. Using multiple linear regression analysis we develop a predictive model for pollutant loads. Of the attributes examined a combination of runoff and the proportion of the stream length draining remnant vegetation was the best predictor. The sediment yield per unit area from a catchment containing no remnant vegetation is predicted to be between 50 and 200 times that of a fully vegetated channel network; total phosphorus between 25 and 60 times; total nitrogen between 1.6 and 4.1 times. There are~48 000 km of streams in the region of which 32% drain areas of remnant vegetation. Of these 17 095 km are above the region's water storage dams. We estimate that decreasing the sediment and phosphorus loads to Moreton Bay by 50% would involve rehabilitating~6350 km of the channel network below the dams; halving the total nitrogen load would require almost complete restoration of the channel network.

The jet erosion test (JET) is a widely applied method for deriving the erodibility of cohesive soils and sediments. There are suggestions in the literature that further examination of the method widely used to interpret the results of these erosion tests is warranted. This paper presents an alternative approach for such interpretation based on the principle of energy conservation. This new approach recognizes that evaluation of erodibility using the jet tester should involve the mass of soil eroded, so determination of this eroded mass (or else scour volume and bulk density) is required. The theory partitions jet kinetic energy flux into that involved in eroding soil, the remainder being dissipated in a variety of mechanisms. The energy required to erode soil is defined as the product of the eroded mass and a resistance parameter which is the energy required to entrain unit mass of soil, denoted J (in J/kg), whose magnitude is sought. An effective component rate of jet energy consumption is defined which depends on depth of scour penetration by the jet, but not on soil type, or the uniformity of the soil type being investigated. Application of the theory depends on experimentally determining the spatial form of jet energy consumption displayed in erosion of a uniform body of soil, an approach of general application. The theory then allows determination of the soil resistance parameter J as a function of depth of scour penetration into any soil profile, thus evaluating such profile variation in erodibility as may exist. This parameter J has been used with the same meaning in soil and gully erosion studies for the last 25 years. Application of this approach will appear in a companion publication as part 2. Copyright © 2017 John Wiley & Sons, Ltd.

Purpose: Elevated sediment loads reduce reservoir capacity and significantly increase the cost of 25 operating water treatment infrastructure making the management of sediment supply to reservoirs of 26 increasing importance. Sediment fingerprinting techniques can be used to model the relative contributions of different sources of sediment accumulating in reservoirs. The goal of this research is 28 to compare geological and statistical approaches to element selection for sediment fingerprinting 29 modelling. 30 Materials and methods: Time-integrated samplers (n=45) were used to obtain source samples from 31 four major subcatchments flowing into the Baroon Pocket Dam in South East Queensland, Australia. 32 The geochemistry of these potential sources were compared to sediment cores (n=12) sampled in the 33 reservoir. Elements that provided expected, observed and statistical discrimination between sediment 34 sources were selected for modelling with the geological approach. Two statistical approaches selected 35 elements for modelling with the Kruskal-Wallis H-test and Discriminatory Function Analysis (DFA). 36 In particular, two approaches to the DFA were adopted to investigate the importance of element 37 selection on modelling results. A distribution model determined the relative contributions of difference 38 sources to sediment sampled in the Baroon Pocket Dam. 39 Results and discussion: Elemental discrimination was expected between one subcatchment (Obi Obi 40 Creek) and the remaining subcatchments (Lexys, Falls and Bridge Creek). Six major elements were 41 expected to provide discrimination. Of these six, only Fe 2 O 3 and SiO 2 provided expected, observed 42 and statistical discrimination. Modelling results with this geological approach indicated 36% (+/-9%) 43 of sediment sampled in the reservoir cores were from mafic-derived sources and 64% (+/-9%) were 44 from felsic-derived sources. The geological and the first statistical approach differed by only 1% (σ 45 5%) for 5 out of 6 model groupings with only the Lexys Creek modelling results differing 46 significantly (35%). The statistical model with expanded elemental selection differed from the 47 geological model by an average of 30% for all 6 models. 48 Conclusions: Elemental selection for sediment fingerprinting therefore has the potential to impact 49 modeling results. Accordingly we believe it is important to incorporate both robust geological and 50 statistical approaches when selecting elements for sediment fingerprinting. For the Baroon Pocket 51 Dam, management should focus on reducing the supply of sediments derived from felsic sources in 52 each of the subcatchments.