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

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.

长期年均取水量限值（LTAAEL）是对河流系统年取水量设定的监管限值。它确保长期内的平均取水量具有可持续性，从而有助于防止环境退化。

在新南威尔士州（NSW），这些限值由水资源共享计划（WSPs）定义。每个WSP概述河流系统的水资源在10年内的分配方式，还明确：

• 各河流系统LTAAEL合规性的评估方法
• 触发不合规行动的条件
• 可采取的合规措施

自然资源委员会定期审查所有WSP，确保各河流系统的取水量不超过设定限值；墨累-达令盆地管理局则每年审查可持续分流限值（SDL）的合规情况。

为评估合规性，我们使用已配置为体现系统WSP开发与管理规则的模型对LTAAEL进行建模（称为LTAAEL模型）。随后将该建模LTAAEL与当前条件下的建模长期年均取水量（LTAAEs）对比——后者通常由年度允许取水量（APT）模型生成。尽管LTAAEL涵盖多种用水类型，合规性评估仍基于总量。我们每年使用现有最佳模型开展此项工作，结果发布于DPE网站。

若河流系统的LTAAE超过LTAAEL，则视为不合规。若满足WSP中的不合规触发条件，将采取相应行动。

本数据集包含由年度扩展LTAAEL模型模拟的各河流系统多监测站流量。尽管模型存在固有局限性，但这些流量可合理反映WSP运行与开发条件下的预期情况，可与其他关键情景模型（如年度允许取水量（APT）模型或无开发（WOD）模型）模拟的流量对比。