Tuckean Swamp Restoration

Department of Primary Industries (Marine Estate Management Authority) commissioned a Cost Benefit Analysis, carried out by the University of NSW. The CBA was determined using practices recognised by NSW Treasury. The key result being that broadscale Tuckean Swamp restoration has 3.4 times more benefits than costs, compared to existing land uses. The benefits outweigh the costs for time horizons longer than 11 years. Most of the benefits accrue to the wider community on the Richmond River.

The Values Study was commissioned by the Tuckean Steering Committee and was carried out by GHD consultants. It involved a wide-ranging set of discussions with Steering Committee members separately, a workshop with the Tuckean Steering Committee to identify the values to be assessed and a multi-criteria assessment (MCA) by consultants GHD assessment of each option (when compared to the current situation). Option 6 - Hinging open the Bagotville Barrage and installing structures upstream of the Tuckean Nature Reserve on all the major drains emerged from the Values Assessment as being the most cost-effective solution to bring about the greatest positive change for water quality

The Tuckean Steering Committee commissioned a report detailing the design and costing of the preferred options from those outlined in the Options Study was prepared by GHD consultants working with Rous County Council as infrastructure managers. Both capital and maintenance costs have been covered for each of the six options. This included safety and operational changes to the Barrage, extending and improving the Stibbards Creek Levee to protect adjacent agricultural land use and new floodgates at the boundary of the Nature Reserve in multiple locations.

It has been known for decades that the artificially enhanced drainage of the Richmond River floodplain is a significant contributor to the water quality issues affecting the lower Richmond River, in particular, blackwater events and acidic discharges containing metal contaminants. A collaborative project, between RCC, NSW Governments Department of Planning and Environment (DPE) and Southern Cross University (SCU), has enhanced the understating of the water quality issues facing the Richmond River. The water quality was monitored in the mid to lower parts of the Richmond River from March 2021 to January 2023. A report analysing the results has been released. A high percentage of samples taken upstream and downstream of the Tuckean did not meet ANZECC guidelines for dissolved oxygen nor pH.

Blackwater events are difficult and complex to address and can be devastating when they occur. The Technical Note includes the most current scientific understanding of how Blackwater is formed, how it impacts the estuary and what needs to occur to reduce the frequency and magnitude of these events. The Technical Note summarises current scientific knowledge of blackwater and results from the recent collaborative Australian Research Council project ‘Episodic estuarine hypoxia: resolving the geochemistry of coastal floodplain blackwaters’ which focused on the Richmond River floodplain. The Technical Note has been developed by Rous County Council and Ballina Shire Council with the input and endorsement of Professor Leigh Sullivan (University of Canberra), Professor Scott Johnston (Southern Cross University) and Dr Vanessa Wong (Monash University).

Project update provided to land owners and stakeholders. Latest outcomes from the Options Study and next steps (3.5 page read). Based on the data collected and existing information from previous studies, a detailed baseline model of the Tuckean Swamp floodplain was developed. The model was constructed to represent the floodplain as it exists today and collected data was input into the model and used to replicate the present day conditions (often referred to as the “Base Case”). Once the existing Base Case was verified, modifications were made within the model and allowed Water Research Labs (UNSW) to test “what if” scenarios of different management options.

This executive summary is a short-read version of the Tuckean Swamp Hydrologic Options. An aim of this study is to improve the overall understanding of the hydrology of Tuckean Swamp and floodplain through extensive field data collection and numerical modelling. With a better understanding of how the site currently functions, different management options can be investigated targeted at decreasing acidic discharges from the site and improving overall water quality. While the environmental benefits are important, it is vital that any hydrologic impacts to the wider floodplain and adjacent landholders are equally considered.

This study identifies the areas of the Tuckean floodplain that are having the greatest impact on water quality in the region, using extensive field data and a conceptual understanding of the site. Using this information, six (6) alternative drainage management options have been developed to address and mitigate some of the issues associated with ASSAn aim of this study is to improve the overall understanding of the hydrology of Tuckean Swamp and floodplain through extensive field data collection and numerical modelling. With a better understanding of how the site currently functions, different management options can be investigated targeted at decreasing acidic discharges from the site and improving overall water quality.

Project update provided to land owners and stakeholders. Latest on Water Quality - Water quality leaving the system over 2018 was largely dependent on the timing, frequency and magnitude of rainfall events. Acid discharge increases when low-lying areas dry out and gradients between groundwater and drains are greatest. During June and July pH of water leaving the system dropped down to below 4. Mid-year samples by the UNSW Water Research Lab team recorded a field pH of 2.08, one of the lowest readings they have ever recorded in NSW. Once groundwater levels recede below drain level, tidal flushing improves water quality again in the lower reaches of the Swamp.

An Echo of Wings: A History of the Tuckean Swamp published. Situated on the Far North Coast of New South Wales, the Tuckean was one of the largest swamps along the coast north of Sydney, in a landscape once full of swamps. Misunderstood and derided throughout much of European history, swamps have now been recognised as among the most productive environments alongside rainforests and coral reefs. It was not until the 1960s that scientific understanding about the critical significance of swamps in the natural environment began to emerge, by which time generations of farming families had made their homes and established communities within such landscapes.

UNSW Water Research Lab researchers present project progress to Tuckean Swamp landholder group. This is a visual slideshow of Drainage Options Scenarios presented by Duncan Rayner.

UNSW Water Research Lab researchers propose possible solutions to improve water quality, which they will test to review the changes to the Swamp.This document outlines a series of modelling scenarios that WRL recommends for the Tuckean floodplain. These scenarios are broad ranging and are intended to provide information on how each option would impact the floodplain, surrounding landholders and water quality in the region. These scenarios are draft suggestions only, based on our conceptual modelling of the site and modelling to date. The description of the scenarios refers to the management sections and general remediation strategies that are outlined in the accompanying documents.

UNSW Water Research Lab researchers utilise data to gain conceptual understanding of Tuckean Swamp.This document provides a brief overview of what acid sulfate soils are, and a conceptual understanding how these soils contribute to poor water quality during dry and wet conditions. Using this understanding, and the substantial field data available, the floodplain has been sub-divided into preliminary management areas which are outlined in the final section of this memorandum. Each section has been prioritised based on its contribution to poor water quality in the region and a brief justification has been provided on each area.

UNSW Water Research Lab researchers set up baseline monitoring of water quality, flow and ground water in the Swamp. The first step in determining possible options to improve water quality in the lower Tuckean Swamp is to perform a hydrologic and hydrodynamic (water movement through the landscape) study of the area. Water monitoring provides data to determine water management options for change to the lower Tuckean catchment that will improve water quality.

We now know that the past modifications to the hydrology of the Tuckean Swamp, largely through floodplain drainage works, has resulted in poor water quality across it’s lower catchment. Several large coastal wetland restorations in NSW have now proven successful in reducing poor water quality being exported from drained swamp situations similar to the Tuckean Swamp. A partnership of organisations has formed to use this new knowledge toward implementing actions for the improvement of water quality at the Tuckean Swamp