Executive Summary The degradation of river catchments by human use does not only have ecological implications but also often decreases in economic value, e.g. erosion removes fertile soils and reduces land productivity. Due to the high connectivity that characterises freshwater ecosystems these negative effects often extend beyond the directly degraded areas, commonly affecting the downstream river reaches, estuaries and coastal waters. In such cases the question may arise how to best plan rehabilitation to reduce land degradation, minimise economic loss, while improving the ecological status of streams and rivers. An efficient rehabilitation plan should specify what to do and where (e.g., rehabilitate a particular gully in the lower catchment or reduce nutrients inputs in the headwaters). This question may be expressed in terms of a single objective, e.g. what can we do to limit sediment transport. More often than not, the question becomes involves more than one objective. For instance, what is the best (as in optimal) way to reduce sediment and maintain economic productivity whilst staying within a given rehabilitation budget. Once we have set ourselves an objective, the search begins for opriate management actions to fu apprlfil them. The Catchment Rehabilitation Planner is a software tool that brings together a collection of methods, models and data to assist SEQ-Queensland's natural resource managers in protecting and improving the health of Moreton Bay and the regions waterways. In the region non-urban diffuse sediment loads have been identified to be a major contributor to poor water quality and aquatic ecosystem health in both freshwater and estuarine/marine systems. The Planner focuses on seeking the most efficient way of reducing sediment transport and improving the ecological status of streams and rivers while minimising the impact in local economy. Given that rehabilitation is an expensive task and usually competes with other uses, the consideration of social, economic and land use factors is an important issue when planning for rehabilitation. Rehabilitation budgets are always under pressure and deciding how to spend them before making costly erroneous decisions is an important issue. For this reason the Catchment Rehabilitation Planner also gives consideration to the cost of each management action ries to find the most efficient way and t of achieving its objectives. The Catchment Rehabilitation Planner consist of three core models i) a sediment budget model allowing examination of one of SE-Queensland main objectives: reducing sediment transport from the catchments, ii) a model which simulate the benefits of rehabilitation on ecosystem status, and iii) model which predicts their implications on economic opportunity costs and management (implementation) costs. These models, together with relevant data, allow us to evaluate a range of 'what-if' scenarios in terms of objectives, budgetary constraints, model parameters and management actions cost structures. The optimisation objectives can be specified as single or multiple objectives. The results of the single-objective evaluations are semi-optimal solutions presented as a collection of tasks: where in the catchment and how much to spend on what type of management actions. Another result is the effect that those actions would have on the (single) objective. Catchment Rehabilitation Planner: SEQ spatial optimisation model 10Jun11 The Planner software can be used in isolation on a single computer or as an easily distributed application via the internet allowing people to share scenarios. The internet-based distribution has the added advantage of automatically updating the software and data without complex installation procedures. The Planner software also allows users to add new catchments through support for data import. This document escribes the software, the underlying models and their implementation. d