Stormwater management

Managing excess or concentrated stormwater runoff from urban and peri-urban catchments can be an important management opportunity. There are several terms to describe these activities, including Integrated Stormwater Management (ISWM) or Water Sensitive Urban Design (WSUD). Urban stormwater runoff can be more than 10 times pre-development volumes and can have significant geomorphic impacts[2]. Intervention approaches include stormwater control measures such as constructed wetlands, raingardens and stormwater tanks.

ISWM/WSUD involves maximising the retention or detention of stormwater and releasing it more slowly and in less concentrated flows. There are many different techniques, often used in combination, and their placement will be highly influenced by the available space, both above and below ground. These systems can manage water volumes, treat water quality and provide amenity (see Treatment systems).

Potential benefits from this intervention:

• Reduced channel erosion of riverbed and banks, by reducing runoff velocities, sediment mobilisation and transport, as well as decreasing the extent of channel incision (deepening and widening)[1].
• Reduced flow disturbance of biota, including macroinvertebrates, fish and vegetation.
• Increased baseflows (through slow release).
• Improved water quality.
• Catchment-scale benefits not directly related to river rehabilitation — including urban greening and cooling, improved amenity, alternative water supplies — can be considered in business-cases for applications.

Potential negative implications from this intervention:

• High cost to implement, maintain and monitor.
• Possible bank erosion caused at outlets.

Intervention considerations:

• Seek appropriate specialist advice and check legal obligations (e.g. permits).
• The key considerations for planning and design include:
  • Set targets for river condition, water balance, flow and water quality regimes.
  • Mimic pre-development water balance (i.e. volume reaching the river should ideally equal pre-development through harvesting and irrigation by finding sufficient demand).
  • Identify stormwater control measures that filter and infiltrate, and have the capacity to store rain.
  • Apply stormwater control measures to all impervious surfaces through catchment-scale planning[3].

Further information on Water Sensitive Urban design can be found here.

Additional information

Publications:

Hawley, R. J. and Vietz, G. J. 2016. Addressing the urban stream disturbance regime, Freshwater Science 35(1):278-292.

Vietz, G.J., M.J. Sammonds, C.J. Walsh, T.D. Fletcher, I.D. Rutherfurd, and M.J. Stewardson. 2014. Ecologically relevant geomorphic attributes of streams are impaired by even low levels of watershed effective imperviousness. Geomorphology, 206:67-78.

Walsh, C. J., Booth, D. B., Burns, M. J., Fletcher, T. D., Hale, R. L., Hoang, L. N., Livingston, G., Rippy, M. A., Roy, A. H., Scoggins, M., Wallace, A. 2016. Principles for urban stormwater management to protect stream ecosystems. Freshwater Science, 35(1):398-411.

Links:

Treatment systems for urban stormwater

Queensland Urban Drainage Manual (QUDM) (Institute of Public Works Engineering Australasia): This manual (QUDM) assists engineers and stormwater designers in the planning, design and management of urban stormwater drainage systems. Note this is a paid publication and it is likely your specialist would have access to the required information.

Queensland Water Quality Guidelines 2009 (Department of Environment and Heritage Protection): This guideline provides values tailored to Queensland streams and regions and provides a framework for applying more locally specific guidelines.

Water by Design (Healthy Land & Water): This resource provides guidance on Total Water Cycle Management and Water Sensitive Urban Design in separate documents.

References

1. ^ Hawley, RJ & Vietz, GJ (1 March 2016), 'Addressing the urban stream disturbance regime', Freshwater Science. [online], vol. 35, no. 1, pp. 278-292. Available at: https://www.journals.uchicago.edu/doi/10.1086/684647 [Accessed 3 June 2022].
2. ^ Vietz, GJ, Sammonds, MJ, Walsh, CJ, Fletcher, TD, Rutherfurd, ID & Stewardson, MJ (February 2014), 'Ecologically relevant geomorphic attributes of streams are impaired by even low levels of watershed effective imperviousness', Geomorphology. [online], vol. 206, pp. 67-78. Available at: https://linkinghub.elsevier.com/retrieve/pii/S0169555X13004777 [Accessed 3 June 2022].
3. ^ Walsh, CJ, Booth, DB, Burns, MJ, Fletcher, TD, Hale, RL, Hoang, LN, Livingston, G, Rippy, MA, Roy, AH, Scoggins, M & Wallace, A (1 March 2016), 'Principles for urban stormwater management to protect stream ecosystems', Freshwater Science. [online], vol. 35, no. 1, pp. 398-411. Available at: https://www.journals.uchicago.edu/doi/10.1086/685284 [Accessed 3 June 2022].

Last updated: 22 June 2022