Stanley B. Grant

Adapting Urban Water Systems to a Changing Climate: Lessons from the Millennium Drought in Southeast Australia

Feature pubs.acs.org/est Adapting Urban Water Systems to a Changing Climate: Lessons from the Millennium Drought in Southeast Australia Stanley B. Grant,* ,†,‡ Tim D. Fletcher, ⊥ David Feldman, § Jean-Daniel Saphores, †,§ Perran L. M. Cook, # Mike Stewardson, ‡ Kathleen Low, † Kristal Burry, ∇ and Andrew J. Hamilton ∥ Department of Civil and Environmental Engineering, E4130 Engineering Gateway, University of California, Irvine, Irvine, California 92697-2175, United States Department of Infrastructure Engineering, Melbourne School of Engineering, Engineering Block D, The University of Melbourne, Parkville 3010, Victoria, Australia Department of Planning, Policy, and Design, 300G Social Ecology I, University of California, Irvine, Irvine, California 92697-7075, United States Department of Agriculture and Food Systems, The University of Melbourne, 940 Dookie−Nalinga Road, Dookie College, Victoria 3647, Australia Melbourne School of Land and Environment, The University of Melbourne, Burnley Campus, 500 Yarra Boulevard, Richmond, Victoria 3121, Australia Water Studies Centre, School of Chemistry, Monash University, Victoria 3800, Australia Melbourne School of Land and Environment, The University of Melbourne, Parkville Campus, 207 Bouverie Street, Victoria 3052, Australia the way Melburnians source and use their water resources and discuss what these changes may portend for other large cities in water-scarce and climate-change-vulnerable regions of the world, in particular, the Southwest region of the United States. MELBOURNE’S WATER SUPPLY Melbourne sources most of its water from protected stream catchments located in uninhabited mountain ash (Eucalyptus regnans) forests to the north and northeast of the city (Figure 1). Runoff from these protected catchments flows by gravity into ten harvesting reservoirs and, from there, through a network of aqueducts and pipelines to storage reservoirs where it is distributed, after minimal treatment, to local service reservoirs. Since the first harvesting reservoir was built in the mid-1800s, Melbourne’s protected catchments have provided the city with a safe, low-energy, and mostly reliable source of high quality drinking water. However, they have also left the city vulnerable to water shortages during periods of very low precipitation. 5 To buffer against water shortages, Melbourne recently invested in various water supply augmentation schemes, including an interbasin transfer pipeline (the North−South or Sugarloaf Pipeline) and the largest desalination plant in the Southern Hemisphere (the Wonthaggi Desalination Plant) (Figure 1). These two projects were built at a capital cost of approximately AU

Australia's Drought: Lessons for California

700 million 6 and AU

From Rain Tanks to Catchments: Use of Low-Impact Development To Address Hydrologic Symptoms of the Urban Stream Syndrome

6 billion, 7 respec- tively, and can deliver annually up to 75 and 150 GL of water to Melbourne; combined, that equates to about 40% of the city’s present day municipal water demand. However, since their completion in 2010 (Sugarloaf Pipeline) and 2012 (Wonthaggi Desalination Plant), neither A LONG HISTORY OF DROUGHT IN MELBOURNE Australia is the world’s driest inhabited continent, and its population is one of the most urban. As of 2010, 89% of Australia’s 21 million inhabitants lived in urban areas. 1 Finding adequate water resources to sustain Australia’s cities is an ongoing challenge. 2 Nowhere is that more apparent than in Melbourne, a coastal city of approximately 4 million people located on the country’s southeastern coast. Over its 166-year history, Melbourne has experienced eight major droughts. The most recent one, known as the Millennium Drought, started in 1997 and lasted more than a decade. By 2009, below-average precipitation and above-average temperatures drained the city’s drinking-water reservoirs and stoked bush fires, including the “Black Saturday” fire that damaged 30% of the city’s water supply catchment and claimed 173 lives. 3 The Millennium Drought also altered public perceptions about global climate change, water conservation, and water-use behaviors, and energized city managers and politicians to adopt a wide range of approaches for augmenting water supplies and conserving water resources, although the contribution of climate change to the Millennium drought, while plausible, remains unproven. 4 In this paper, we explore how the Millennium Drought changed

First-order contaminant removal in the hyporheic zone of streams: physical insights from a simple analytical model.

COMMENTARY Refl ective scientifi c treatises Strengthening citizen science LETTERS I BOOKS I POLICY FORUM I EDUCATION FORUM I PERSPECTIVES LETTERS edited by Jennifer Sills 28 MARCH 2014 sumptive activities—such as daytime lawn watering and car washing—to rules promot- ing efficient water use—such as require- ments for shutoff valves on hoses. Out of those temporary restrictions, permanent restrictions grew. Some areas in Australia still restrict daytime sprinkler use. Perhaps most relevant for worried Californians is how the Australian public received these changes. Studies cite an overall spirit of goodwill and cooperation fostered by the stress of drought (6). The Millennium Drought brought about profound changes in Australians’ concep- tion of the environment, climate change, and water. The sticking power of those les- sons and the success of the resulting policies and strategies will be tested by the next big drought. One lesson California can glean from the Australian experience is empower- ment. Individuals making frugal water deci- sions can make a big difference in urban areas. Water markets and other measures that increase the fl exibility of irrigation farmers in their response to drought can have big payoffs. Sustaining critical environmental water requirements will provide the basis for postdrought environmental recovery. A spirit of cooperation rather than contention can prevail even when tough decisions are made to address the needs of farmers and city residents. AMIR AGHAKOUCHAK, 1 * DAVID FELDMAN, 1 MICHAEL J. STEWARDSON, 2 JEAN-DANIEL SAPHORES, 1 STANLEY GRANT, 1,2 BRETT SANDERS 1 The Henry Samueli School of Engineering, University of California, Irvine, Irvine, CA 92697, USA. 2 Melbourne School of Engineering, The University of Melbourne, Parkville, VIC 3010, Australia. *Corresponding author. E-mail: amir.a@uci.edu References 1. A. I. Dijk et al., Water Resources Res. 49, 1040 (2013). 2. Z. Hao et al., Sci. Data 1, 1 (2014). 3. S. Dolnicar, A. I. Schafer, J. Environ. Manage. 90, 888 VOL 343 SCIENCE www.sciencemag.org Published by AAAS Downloaded from www.sciencemag.org on March 27, 2014 MOST OF CALIFORNIA IS SUFFERING FROM AN extreme drought, and storage levels in the major reservoirs are well below historic lev- els. For the past several months, an unusually stubborn ridge of high pressure off the West Coast of the United States has been blocking normal winter storms and the rain they carry. California’s history of drought has led to state- wide strategies to save water, but Californian residents and policy-makers can do even more: They can look to the story of Australia’s experi- ence with a drought so intense and long-lasting that it was dramatically dubbed the Millennium Drought (1). The Millennium Drought lasted from 1997 until late 2009 (2). Australia’s economy and environment were hit hard. The drought accel- erated the same trends facing farmers in devel- oping countries worldwide: Small farms were squeezed out. Midsized farms were most vul- nerable because they could neither achieve the economies of scale available to larger produc- ers nor buffer losses with off-farm employ- ment like the smallest farms could. Amazingly, despite blows to crop yields and Dried out. As of February 2014, most of California is in Extreme to Exceptional Drought (see red and livestock numbers, Australia’s rate of growth in dark red areas on map). agricultural production has quickly returned to predrought trends. The impacts of this major drought on irrigation communities were buffered by some critical water reforms. These included: (i) well-developed water markets that allowed water trade to farmers in the greatest need; (ii) modernization of irrigation infrastructure that increased the effi ciency of water delivery; and (iii) establishment of clear water entitlements for the environment that protected critical refuge habitats and populations as water availability declined. The use of water markets was particularly critical. More than 40% of annual water alloca- tions were traded at the height of the drought in 2007. For example, increased water prices allowed dairy farmers to sell their allocation and purchase fodder with the proceeds rather than irrigate pasture. Fruit growers and other producers who needed to maintain irrigation through- out the drought could purchase the dairy farmers’ water to keep their operations viable. In urban areas, strategies to increase supply and decrease demand were brought to bear. Expensive desalination and water recycling plants were built. Australians were more comfort- able with the desalinated water (3, 4), despite the recycled water’s safety and the desalination plants’ greater cost and large carbon and environmental footprints (4). Between 2002 and 2009, per capita municipal water use in southeast Australia decreased by nearly 50% (5). Water use restrictions ranged from outright bans of conspicuously con- CREDIT: DATA FROM THE GLOBAL INTEGRATED DROUGHT MONITORING AND PREDICTION SYSTEM (GIDMAPS) (2) Australia’s Drought: Lessons for California

Flipping the thin film model: Mass transfer by hyporheic exchange in gaining and losing streams

Catchment urbanization perturbs the water and sediment budgets of streams, degrades stream health and function, and causes a constellation of flow, water quality, and ecological symptoms collectively known as the urban stream syndrome. Low-impact development (LID) technologies address the hydrologic symptoms of the urban stream syndrome by mimicking natural flow paths and restoring a natural water balance. Over annual time scales, the volumes of stormwater that should be infiltrated and harvested can be estimated from a catchment-scale water-balance given local climate conditions and preurban land cover. For all but the wettest regions of the world, a much larger volume of stormwater runoff should be harvested than infiltrated to maintain stream hydrology in a preurban state. Efforts to prevent or reverse hydrologic symptoms associated with the urban stream syndrome will therefore require: (1) selecting the right mix of LID technologies that provide regionally tailored ratios of stormwater harvesting and infiltration; (2) integrating these LID technologies into next-generation drainage systems; (3) maximizing potential cobenefits including water supply augmentation, flood protection, improved water quality, and urban amenities; and (4) long-term hydrologic monitoring to evaluate the efficacy of LID interventions.

Small drains, big problems: The impact of dry weather runoff on shoreline water quality at enclosed beaches

A simple analytical model is presented for the removal of stream-borne contaminants by hyporheic exchange across duned or rippled streambeds. The model assumes a steady-state balance between contaminant supply from the stream and first-order reaction in the sediment. Hyporheic exchange occurs by bed form pumping, in which water and contaminants flow into bed forms in high-pressure regions (downwelling zones) and out of bed forms in low-pressure regions (upwelling zones). Model-predicted contaminant concentrations are higher in downwelling zones than upwelling zones, reflecting the strong coupling that exists between transport and reaction in these systems. When flow-averaged, the concentration difference across upwelling and downwelling zones drives a net contaminant flux into the sediment bed proportional to the average downwelling velocity. The downwelling velocity is functionally equivalent to a mass transfer coefficient, and can be estimated from stream state variables including stream velocity, bed form geometry, and the hydraulic conductivity and porosity of the sediment. Increasing the mass transfer coefficient increases the fraction of streamwater cycling through the hyporheic zone (per unit length of stream) but also decreases the time contaminants undergo first-order reaction in the sediment. As a consequence, small changes in stream state variables can significantly alter the performance of hyporheic zone treatment systems.

Predictive Power of Clean Bed Filtration Theory for Fecal Indicator Bacteria Removal in Stormwater Biofilters

The exchange of mass between a stream and its hyporheic zone, or “hyporheic exchange”, is central to many important ecosystem services. In this paper we show that mass transfer across the streambed by linear mechanisms of hyporheic exchange in a gaining or losing stream can be represented by a thin film model in which: (a) the mass transfer coefficient is replaced with the average Darcy flux of water downwelling into the sediment; and (b) the driving force for mass transfer is “flipped” from normal to the surface (concentration difference across a boundary layer) to parallel to the surface (concentration difference across downwelling and upwelling zones). Our analysis is consistent with previously published analytical, computational, and experimental studies of hyporheic exchange in the presence of stream-groundwater interactions, and links stream network, advection-dispersion, and stochastic descriptions of solute fate and transport in rivers. This article is protected by copyright. All rights reserved.

CalSWIM: A Wiki–Based Data Sharing Platform

Enclosed beaches along urban coastlines are frequent hot spots of fecal indicator bacteria (FIB) pollution. In this paper we present field measurements and modeling studies aimed at evaluating the impact of small storm drains on FIB pollution at enclosed beaches in Newport Bay, the second largest tidal embayment in Southern California. Our results suggest that small drains have a disproportionate impact on enclosed beach water quality for five reasons: (1) dry weather surface flows (primarily from overirrigation of lawns and ornamental plants) harbor FIB at concentrations exceeding recreational water quality criteria; (2) small drains can trap dry weather runoff during high tide, and then release it in a bolus during the falling tide when drainpipe outlets are exposed; (3) nearshore turbulence is low (turbulent diffusivities approximately 10(-3) m(2) s(-1)), limiting dilution of FIB and other runoff-associated pollutants once they enter the bay; (4) once in the bay, runoff can form buoyant plumes that further limit vertical mixing and dilution; and (5) local winds can force buoyant runoff plumes back against the shoreline, where water depth is minimal and human contact likely. Outdoor water conservation and urban retrofits that minimize the volume of dry and wet weather runoff entering the local storm drain system may be the best option for improving beach water quality in Newport Bay and other urban-impacted enclosed beaches.

Variation in reach-scale hydraulic conductivity of streambeds

Green infrastructure (also referred to as low impact development, or LID) has the potential to transform urban stormwater runoff from an environmental threat to a valuable water resource. In this paper we focus on the removal of fecal indicator bacteria (FIB, a pollutant responsible for runoff-associated inland and coastal beach closures) in stormwater biofilters (a common type of green infrastructure). Drawing on a combination of previously published and new laboratory studies of FIB removal in biofilters, we find that 66% of the variance in FIB removal rates can be explained by clean bed filtration theory (CBFT, 31%), antecedent dry period (14%), study effect (8%), biofilter age (7%), and the presence or absence of shrubs (6%). Our analysis suggests that, with the exception of shrubs, plants affect FIB removal indirectly by changing the infiltration rate, not directly by changing the FIB removal mechanisms or altering filtration rates in ways not already accounted for by CBFT. The analysis presented here represents a significant step forward in our understanding of how physicochemical theories (such as CBFT) can be melded with hydrology, engineering design, and ecology to improve the water quality benefits of green infrastructure.

Fighting drought with innovation: Melbourne's response to the Millennium Drought in Southeast Australia

Organizations increasingly create massive internal digital data repositories and are looking for technical advances in managing, exchanging and integrating explicit knowledge. While most of the enabling technologies for knowledge management have been used around for several years, the ability to cost effective data sharing, integration and analysis into a cohesive infrastructure evaded organizations until the advent of Web 2.0 applications. In this paper, we discuss our investigations into using a Wiki as a web–based interactive knowledge management system, which is integrated with some features for easy data access, data integration and analysis. Using the enhanced wiki, it possible to make organizational knowledge sustainable, expandable, outreaching and continually up–to–date. The wiki is currently under use as California Sustainable Watershed Information Manager. We evaluate our work according to the requirements of knowledge management systems. The result shows that our solution satisfies more requirements compared to other tools.