Monitoring guidelines To quantify nitrogen removal in vegetated water treatment systems (constructed treatment wetlands and vegetated drains)

Abstract

This document provides guidance on designing water monitoring programs for calculating nitrogen removal by vegetated water treatment systems, including constructed treatment wetlands or vegetated drains. The document focuses on monitoring of vegetated water treatment systems used to reduce nitrogen leaving farms prior to entering natural waterways and wetlands in tropical and sub-tropical Queensland. It aims to enable estimation of nitrogen reduction as accurately as possible within the constraints of monitoring in highly variable environments.

This document aims to provide consistency in monitoring approaches, enabling comparison of different vegetated water treatment systems and synthesis of information across different projects and sites to further knowledge on the performance (and limitations) of vegetated water treatment systems in different climatic regions, farm types and water regimes. The target audience includes research personnel, natural resource managers and land managers interested in monitoring vegetated water treatment systems to assess water quality improvement.

The document is written with the specific conditions and constraints of agricultural production areas in mind. Although vegetated water treatment systems are also used to treat urban stormwater and wastewater such as treated sewage effluent, the design, operating environment, and monitoring budget can be different. The principles in these guidelines can be adapted to these other land uses, although the objective of the vegetated water treatment system, flow regime(s) and nitrogen form(s) may be different thereby influencing the purpose of the monitoring project.

The methods outlined in this document have been compiled from methodologies described in both peer-reviewed publications and reports, together with technical input and advice from scientists and natural resource management officers involved in implementing and monitoring vegetated water treatment systems in Queensland. As monitoring methods, technologies and equipment are constantly evolving, the reader should undertake their own investigations in designing the monitoring program to ensure it meets the specific purpose of the monitoring project.

Detailed information on different types of vegetated water treatment systems and treatment processes are available on the Queensland Government WetlandInfo website wetlandinfo.des.qld.gov.au.