Environment Southland is gearing up to complete a high-definition river survey in the coming weeks. The project aims to measure the amount of gravel build-up in the Mataura and Waikaia rivers. The contract was awarded to Landpro in February 2022, to survey the rivers using new technology relying on light detection and ranging equipment. This new approach offers a huge increase in the amount of data gained, with 3-dimensional data of the entire river compared to cross-section methods for around the same cost. The survey data will shed light on how much gravel and sediment is in the rivers, where it’s sitting, and the potential impact. The capture component of the project will take approximately one week.
Southland farmers have been concerned about the gravel build-up, as it washes down from the mountains and changes the course of the rivers. This impacts the local environment, eroding banks and felling trees, with the potential to impact local pastures, infrastructure, and increase the risk of floods in local townships. Locals expressed their concerns following flooding in 2021 which impacted surrounding farmers’ land and brought even more gravel down into the main river systems. Locals have called for extracting the gravel build-up from the rivers to minimise risk. Surveying is an essential part of the process, providing the right data to navigate the best solutions and resolve the gravel issue.
While Landpro has been using LiDAR for the last 5 years delivering cross section data for the land-based component of sections, this survey will be the first time in New Zealand that such enabling data will be used by council to make really informed decisions. Landpro’s geospatial team will be working closely with the Environment Southland team to assist with data multiplication of the dataset ensuring the final data is of the most benefit to Southland.
Surveying is due to start Early-March and the data gathered will be delivered to the Catchment Operations team but will be widely used across different teams within council.