Water Modelling-Modelled Data-Long-term average annual extraction limit (LTAAEL)-Peel

Long-term average annual extraction limit (LTAAEL) is a regulatory limit set on annual water extractions from a river system. It ensures that average extractions over the long term are sustainable, and thus help prevent environmental degradation.\r\n\r\nIn NSW these limits are defined by water sharing plans (WSPs). Every WSP outlines how the water in a river system will be shared over a 10-year period. They also define:\r\n\r\n• how LTAAEL compliance is to be assessed for each river system\r\n\r\n• what conditions will trigger noncompliance action\r\n\r\n• what compliance action can be taken.\r\n\r\nThe Natural Resources Commission regularly reviews all WSPs to ensure extractions from each river system are within the limits set, and the Murray-Darling Basin Authority reviews sustainable diversion limit (SDL) compliance each year.\r\n\r\nTo assess compliance, we model LTAAEL using a model that has been configured to represent the development and management rules defined by a system WSP (this refers to as LTAAEL model). We then compare this modelled LTAAEL with the modelled under current conditions long-term average annual extractions (LTAAEs) (which are usually those modelled by the annual permitted take, or APT, model). Although, the LTAAEL includes multiple types of water use, the compliance assessment is based on the total. We do this annually using the best available models, and the outcomes are published on the DPE website.\r\n\r\nWhere river system’s LTAAE exceed LTAAEL, the system is considered noncompliant. If the noncompliance trigger conditions in the WSP are met, noncompliance action is taken.\r\n\r\nThe data set provided contains flows at several gauges in each river system, as simulated by the annually extended LTAAEL model. Notwithstanding the model’s inherent limitations, these are a fair representation of those we would expect under WSP operation and development conditions. They can be compared with flows simulated by other key scenario models, such as annual permitted take (APT) model or without development (WOD) model.

长期年均取水限额（Long-term average annual extraction limit, LTAAEL）是针对河流水系年度取水行为设定的监管限值，旨在保障长期平均取水行为具备可持续性，从而防范环境退化。

在新南威尔士州（New South Wales, NSW），此类限值由水资源共享计划（Water Sharing Plans, WSPs）确定。每份水资源共享计划都会明确某一河流水系的水资源在10年周期内的分配方案，同时还会规定：

• 各河流水系的LTAAEL合规性评估方式
• 触发违规处置措施的情形
• 可采取的合规处置措施。

自然资源委员会（Natural Resources Commission）会定期对所有水资源共享计划进行审查，以确保各河流水系的取水量符合设定限值；墨累-达令流域管理局（Murray-Darling Basin Authority）则每年都会开展可持续转移限额（Sustainable Diversion Limit, SDL）的合规性审查工作。

为开展合规性评估，我们会通过一套适配某河流水系水资源共享计划所规定的开发与管理规则的模型对LTAAEL进行模拟（该模型即LTAAEL模型）。随后，我们会将该模拟得到的LTAAEL，与当前工况下模拟得到的长期年均取水量（Long-term average annual extractions, LTAAEs）进行比对——后者通常由年度许可取水量（Annual Permitted Take, APT）模型模拟生成。尽管LTAAEL涵盖多种类型的用水行为，但合规性评估将以总取水量为依据。我们每年都会采用当前最优的模型开展此项工作，并将评估结果发布在规划与环境部（Department of Planning and Environment, DPE）的官方网站上。

当某河流水系的LTAAEs超出LTAAEL时，该水系即被认定为合规不合格。若满足水资源共享计划中规定的违规触发条件，则将启动违规处置程序。

本次提供的数据集包含各河流水系内多个水文监测站的径流量数据，该数据由年度更新版LTAAEL模型模拟生成。尽管该模型存在固有局限性，但这些数据仍能够合理反映水资源共享计划运行与开发场景下的预期径流量情况。可将其与其他关键情景模型的模拟径流量进行比对，例如年度许可取水量（APT）模型或无开发情景（Without Development, WOD）模型的模拟结果。