Groundwater Drainage - Should I Dig?

Описание: Key references
DPIRD’s webpage & Notice of Intent to Drain application form: Groundwater drainage
https://www.agric.wa.gov.au/water-man...
Department of Water’s GHD’s Review of inland drainage research (2003 – 2015)
https://www.wa.gov.au/system/files/20...


“Groundwater Drainage - Should I Dig?”

This video outlines the preferred decision-making process for landholders before constructing a groundwater drain.

The video features Department of Primary Industries and Regional Development (DPIRD) Senior Technical Officer John Firth on location at DPIRD’s Katanning Research Station (KRS) during the planning and construction of an integrated saltland rehabilitation site that includes groundwater drainage.

The location is 5km east of the Katanning townsite which is located 290km SW of Perth in the Western Australian wheatbelt and receives an average annual rainfall of 450mm.

There are several critical pre-planning messages given that groundwater drainage is expensive, the downstream environmental impacts can be detrimental, and that landforms patterns and soil types can significantly limit the effectiveness of groundwater drains.

Using the KRS case study John provides practical guidance on how to make specific site assessments including for: understanding the soil properties; the water table depth; the lateral groundwater flow rates; the amount and quality of the water being discharged, including its acidity. He explains in a straightforward manner how this information was incorporated into the Notice of Intent to Drain application for the KRS case study.

In the same way landholders planning earthworks must lodge a Notice of Intent to Drain with the Commissioner of Soil and Land Conservation at least 90 days before proceeding.

A (DPIRD) officer will undertake a site inspection and discuss the proposal with the landholder to identify any potential land degradation risks.

Key tips for an application include:

1. Submit Notice of Intent to Drain (requirement of the Soil and Land Conservation Regulations 1992).
2. Double levees on both sides of drain
3. Construct Test Pits
4. Identify the discharge point.
5. Communicate with downstream neighbours.

John outlines the following information required for the Notice of Intent to Drain:

Details of property owners from commencement to the discharge points
Aerial photograph or plan of the site including adjacent land.
Description of person/company undertaking the excavation works.
Cross-section plan of the drain including levee banks, separation of surface water etc
Approval/consent from other public authorities
Landholders are responsible for all the above

Video II sequel captures implementation techniques.

It explains the construction techniques, specifically relating to the groundwater drainage applied during the implementation of the KRS integrated saltland rehabilitation site.

These include:
1. the planning from the discharge point, working upstream.
2. installation of soil pits prior to construction.
3. separation of the groundwater from the surface water.
4. integration of the biodiversity revegetation

Marginal Soils and Saltland Management

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