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QWP Newsletter July 2024

QLD Water Engineering Panel

Dealing with water in all its forms

发布日期: 2024年7月8日

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July 2024 - News in brief

Welcome!

?THIS MONTH’S FEATURE

Seeing the floods through the trees: Using adaptive shortwave infrared thresholds to map inundation under wooded wetlands

Journal: Hydrological Processes

Leo Lymburner,?Catherine Ticehurst,?Maria Fernanda Adame,?Ashmita Sengupta,?Emad Kavehei

?Abstract

Accurate information about the extent, frequency and duration of forest inundation is required to inform ecological, biophysical and hydrological models and enables floodplain managers to quantify the efficacy of flood mitigation/modification activities. Open water classifiers derived from optical remote sensing typically underestimate or fail to detect floodplain forest inundation. This paper presents a new method for detecting forest inundation dynamics using freely available Landsat and Sentinel 2 data, referred to as short-wave infrared mapping under vegetation. The method uses a dynamic threshold that accounts for the additional shortwave infrared reflectance caused by the presence of tree canopies over floodwater. The method is demonstrated at five Ramsar listed River Red Gum floodplain forest wetlands in southeastern Australia. Accuracy assessment based on independent drone imagery from a wide range of vegetated wetlands showed an absolute accuracy of 67%–70% and a fuzzy accuracy of 81%–83%. We found the method is conservative, and underestimates inundation (16%–18%) but very rarely misclassifies dry pixels as inundated (0.3%–0.6%). When compared to river gauge data, the method shows similar trends to an open water classifier (i.e., the area of inundated vegetation increases with increasing river height). The method is conservative compared to lidar-based floodplain inundation models but can be applied wherever cloud-free scenes of Landsat or Sentinel 2 have been acquired, thereby enabling floodplain managers with the ability to quantify changes in inundation dynamics in places/time-periods where lidar is unavailable.

Open Access: https://onlinelibrary.wiley.com/doi/10.1002/hyp.15174

HAVE YOUR SAY (June repeat)

In case you missed Ocean Protect’s Daniel Rider in their last months’ webinar about the WSUD Maintenance Compliance Framework, you can access the recording and slides at oceanprotect.com.au/webinars. During the webinar, Daniel answered a range of questions to take the 200+ attendees beneath the surface of the Framework to help them understand the project. ? You can access the Framework via wsudcompliance.com.au/resources. The Framework is in a consultation period right now until August 19th 2024 and it is vital to receive feedback and input from relevant stakeholders, such as yourself.

QUEENSLAND WATER PANEL (QWP) TECHNICAL EVENTS - EXPRESSION OF INTEREST

Calling for presentations on coastal, maritime, marine and ocean engineering projects:

The Queensland Water Panel are hosting a coastal technical session on 11 September in Brisbane.? We are inviting local presentation on topics including coastal engineering, maritime and marine development, dredging, ports or any other salt-water focussed project.? More details of the technical session will be shared in the coming months, which typically include an evening time slot after work, some nibbles and drinks and a chance to meet up with colleagues working in this field. ?

If you have a project you are willing to present (expect 10-15 mins) please email the Queensland Water Panel at [email protected] with the subject: “coastal technical session” with a brief outline of your topic.