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

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）是针对河流系统年度取水行为设定的监管限值，其旨在确保长期平均取水量维持在可持续水平，从而助力防范环境退化。 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）界定。所有WSPs均会明确某一河流系统的水资源在10年周期内的分配方案，同时还会界定： • 如何针对各河流系统开展LTAAEL合规性评估 • 触发不合规处置的具体条件 • 可采取的合规处置措施 自然资源委员会会定期对所有WSPs开展审查，以确保各河流系统的取水量符合既定限值；墨累-达令流域管理局则每年对可持续分流限额（Sustainable Diversion Limit, SDL）的合规情况进行核查。 为开展合规性评估，我们采用已配置为匹配系统WSP所规定的开发与管理规则的模型对LTAAEL进行建模（该模型称为LTAAEL模型）。随后将该建模得到的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）进行对比——后者通常由年度许可取水量（Annual Permitted Take, APT）模型模拟得出。尽管LTAAEL涵盖多种取水类型，但合规性评估将以总取水量为依据。我们每年会采用当前最优的模型开展上述评估，评估结果将发布于规划与环境部（DPE）官网。 当某一河流系统的LTAAEs超出LTAAEL时，该系统即被认定为不合规。若满足WSPs中规定的不合规触发条件，则将启动不合规处置流程。 本次提供的数据集包含各河流系统中多个监测站点的流量数据，这些数据由年度拓展版LTAAEL模型模拟生成。尽管该模型存在固有局限性，但这些数据仍能合理反映WSPs运行与开发工况下的预期流量情况，可将其与其他关键情景模型模拟得到的流量数据进行对比，例如年度许可取水量（APT）模型或无开发（WOD）模型的模拟结果。