Restoration of stormwater retention capacity at the allotment-scale through a novel economic instrument

Abstract

Urbanisation results in changes to runoff behaviour which, if not addressed, inevitably degrade receiving waters. To date, most stormwater management has focussed on the streetscape and public open space. Given that much of the catchment imperviousness is located on private land, we developed and tested a novel economic instrument (a uniform price auction) for encouraging allotment-scale stormwater retention. We evaluated bids using an integrated environmental benefit index (EBI), based on the ability of the proposed works to reduce runoff frequency, pollutant loads and to reduce potable water demand. The uniform price auction resulted in 1.4 ha of impervious areas being effectively 'disconnected' from the stormwater system. The EBI provided an objective and transparent method of comparing bids, which varied in the type of works proposed (e.g. rainwater tank, rain-garden), the cost and the resulting environmental benefit. Whilst the pilot auction was a success, the public subsidy of works undertaken was around 85%, meaning that property owners a relatively small private benefit in the works. Future auction rounds will be revised to (i) test an EBI which is more focussed on the protection of streams (assessing changes to runoff frequency, baseflow volumes and water quality) and (ii) provide an auction process which is simpler to understand, and provides greater practical support for landholders who wish to undertake works.

Small Drains, Big Problems: The Impact of Dry Weather Runoff on Shoreline Water Quality at Enclosed Beaches

“…40−42 A number of large-scale studies are currently underway to evaluate the performance (and incentivize the adoption) of green infrastructure for capturing both dry and wet weather runoff in urban streams. 43 The results of these latter studies may prove useful for managing dry weather runoff at enclosed beaches, as technologies and incentive strategies that are effective in urban streams may also be effective in urban-impacted coastal embayments.…”

Buffering capacity of paddy field as the reservoir of rainwater and surface runoff in the Lowokwaru subdistrict, Malang, East Java

“…Whereas in July when precipitation reaches its lowest, the area of Lowokwaru Subdistrict produces surface run-off water of 133,760 m 3 and 150,480 m 3 . As an endeavour to anticipate the risk of flood, the Government of City of Malang have to reproduce more coveage vegetation that are capable of enhancing rainwater infiltration into the ground, repair and upgrade the capacity of drainage, and build run-off reservoir (Sieker dan Klein, 1998;Furumai et al, 2005;Fletcher et al, 2011;Hutchinson et al, 2011). To effectively and efficiently replace the water storing function of paddy field, those water reservoir should be placed dispersedly to cover more areas.…”

Use and Utility: Exploring the Diversity and Design of Water Models at the Science-Policy Interface

“…The model aims at supporting strategic planning, by focussing on evidence-based quantification of the benefits of urban green infrastructure (GI) initiatives in order to develop business cases that are both robust and water sensitive [90]. The model is capable of: (1) improving stream health impacts based on the effectiveness of WSUD in mitigating runoff volumes, frequency and pollutant concentrations [91][92][93][94]; (2) assessing changes in flow frequency and reduction of geomorphic impact on streams based on the stream erosion index [95] and; (3) mitigating the urban heat island effect through urban greening and retaining water in the landscape [96]. Other modules are still under development including a future climate module, which will draw from a database of future rainfall projections for major Australian cities and can be used independently or as input data for future climate scenarios [97,98].…”