# Tauranga Harbour issues _Mangroves, biosecurity, loss of sea grass habitat, sea lettuce and sedimentation are all issues that  affect water quality and our ability to enjoy the harbour._ As Tauranga continues to grow and evolve, so do the pressures on our harbour. Population growth, land development, and economic activity have all had an effect on Tauranga Harbour. We are working with our communities, iwi and hapū, as well as local industries, to restore and protect it. ## What we are doing - Addressing nutrient pollution through rules and policies in the [Bay of Plenty Regional Natural Resources Plan.](https://www.boprc.govt.nz/your-council/plans-and-policies/plans/regional-plans/regional-natural-resources-plan/ "Regional Natural Resources Plan") - Our [Land Management](https://www.boprc.govt.nz/environment/our-catchments/eastern-bay-of-plenty-catchments/#land-management-officers "Eastern Bay of Plenty Catchments") team and [Focus Catchments Programme](https://www.boprc.govt.nz/environment/fresh-water/focus-catchments/ "Focus catchments") work with landowners to reduce runoff by supporting fencing, planting, nutrient budgeting, and wetland creation. - Monitor nutrient levels in the harbour and share this data on [LAWA](https://www.lawa.org.nz/explore-data/bay-of-plenty-region/estuaries/tauranga-harbour "LAWA") - [View the latest nutrient report for Tauranga Harbour](https://atlas.boprc.govt.nz/api/v1/edms/document/A4160941/content "nutrient report document"). ## What we are doing - We’ve set clear rules and policies through the [Bay of Plenty Regional Natural Resources Plan](https://www.boprc.govt.nz/your-council/plans-and-policies/plans/regional-plans/regional-natural-resources-plan/ "Regional Natural Resources Plan") to help manage sediment entering our waterways and harbour. - Our [Land Management team](https://www.boprc.govt.nz/environment/our-catchments/eastern-bay-of-plenty-catchments/#land-management-officers "Eastern Bay of Plenty Catchments") and [Focus Catchments Programme](https://www.boprc.govt.nz/environment/fresh-water/focus-catchments/ "Focus catchments") work closely with landowners to reduce sediment runoff—this includes retiring and planting steep or erosion-prone land, and creating riparian buffers or wetlands. - We support proven solutions like building detainment bunds and detention dams to trap sediment before it reaches streams and rivers. - We monitor sediment levels and mud content across the harbour and share this data on LAWA Estuaries. - Check out the latest [sedimentation report for Tauranga Harbour](https://atlas.boprc.govt.nz/api/v1/edms/document/A4108365/content "sedimentation report"). ## What we are doing Council is working with landowners and industry to reduce sedimentation which exacerbates mangrove spread.  We also support estuary care groups in their restoration work. See how you can get involved here: [Estuary Care groups](https://www.boprc.govt.nz/living-in-the-bay/volunteer/volunteering-and-environmental-care-groups/) As a volunteer, if you would like to manage mangroves in your area, visit [Managing mangroves](https://www.boprc.govt.nz/environment/coast-and-ocean/harbours/tauranga-harbour/managing-mangroves/)  to see what activity is permitted in your area. ## What we are doing Council has been undertaking a range of saltmarsh restoration and enhancement projects in recent years, including the re-wetting of previously drained land to restore saltmarsh. We support landowners to undertake environmental programmes on their properties to provide biodiversity and water quality benefits, supported by the [Environmental Programme Grants Policy](https://www.boprc.govt.nz/living-in-the-bay/community-funding/environmental-programme-grants-policy/ "Environmental Programme Grants Policy"). We have undertaken research to investigate suitable site locations for [saltmarsh restoration](https://atlas.boprc.govt.nz/api/v1/edms/document/A4275662/content "Potential restoration sites for saltmarsh in a changing climate"), and partnered with various organisations to undertake blue carbon measurements, to track how effective our local saltmarsh is at storing [blue carbon](https://atlas.boprc.govt.nz/api/v1/edms/document/A4884489/content "blue carbon"). We also have an estuarine wetland monitoring network, which includes the use of Surface Elevation Tables to see whether saltmarsh will keep pace with rising sea levels. ## More info about seagrass recovery This recovery includes subtidal seagrass, which remains permanently underwater — a promising sign that water clarity and sediment conditions have improved enough to support regrowth. These improvements align with our river water quality data, which shows positive trends in reduced sediment and nutrient levels at many sites around the harbour. Areas near the harbour entrance with little land runoff or influence from other catchments have shown the smallest decline in seagrass abundance. ![Picture 1, Picture](https://www.boprc.govt.nz/media/jyrmcfhe/blob.png) *Change in seagrass extent in Tauranga Harbour. Green = most recent expansion, grey = 2022 seagrass overlap with 1959, and red = areas of seagrass lost from 1959 to 2022.* A variety of stressors impact on seagrass, including sedimentation and reduced light availability, nutrient enrichment, marine heatwaves, physical disturbance (e.g. loss from reclamation, dredging, anchoring and moorings), waterfowl grazing and disease. [See our latest report on seagrass](https://atlas.boprc.govt.nz/api/v1/edms/document/A4703471/content "Sea grass report"). ## What we are doing We are responding to community concerns about sea lettuce in three ways: 1. **Reducing the amount of nutrients entering Tauranga Harbour** by working with land owners, business owners, local councils and the wider community to: - - Reduce diffuse nutrient sources such as from agricultural runoff and nutrients that drain through the soil and into groundwater which eventually enters the harbour. 1. - Prevent point sources of nutrients such as from septic tank seepage and storm water drains. 2. **Investing in monitoring** to continue to understand the relationships between nutrients and sea lettuce (and other algae) growth. 3. **Reducing the public nuisance factor** and hydrogen sulphide risk in the most severe sea lettuce bloom years by working with Tauranga City and Western Bay of Plenty District Councils to remove sea lettuce from high use public areas around the Tauranga Harbour (where feasible and affordable). Wherever possible, the sea lettuce is  dewatered and taken for composting  along with other green waste. In the rare instances that the collected sea lettuce is too badly decomposed, contaminated with sand or there’s too much of it for the compost facility to handle, it may be disposed of to landfill. ## What you can do You can help manage sea lettuce by collecting it from the foreshore and using it as a fertiliser or compost supplement in your garden. Wash it and use it sparingly to avoid salt build-up in your soil. Find out more in this [Sea Lettuce and the Garden booklet](https://atlas.boprc.govt.nz/api/v1/edms/document/A3888843/content), produced by Tauranga HarbourWatch Inc. [Read our latest snapshot report on sea lettuce](https://atlas.boprc.govt.nz/api/v1/edms/document/A3804713/content "sea lettuce report"). ## Other nuisance macroalgae species There are other species of algae that can create blooms in Tauranga Harbour, and in recent years we have seen a rise in the abundance of a variety of filamentous algae blooms. These tend to begin growing on the intertidal sandflats on top of seagrass beds, and can create nuisance quantities of algae, which can interfere with fishing and boating activities. These can also create a smell and mess when they get pushed into the high shore and break down. The blooms are likely driven by warm water conditions and excess nutrients, however we need to continue to invest in research to understand how we might manage these in the future. ![microalgae](https://www.boprc.govt.nz/media/x5zl1jdq/microalgae.jpg) *Green and red filamentous algae.*