Sustainable Rivers Audit Zone Layer

In the process of constructing the SRA valley zones, the 23 SRA valleys were first defined based on the Australian Water Resources Council (AWRC) catchment layer, with alteration being done using the following principles: 1. Where possible, valley boundaries were mapped along areas of highest elevation (ridges); 2. Where possible, river channels and State borders were not used to define the boundaries of a valley ("one river" principle) 3. Larger areas with vastly differing hydrology/climate/geomorphology were not combined. 4.The hydrologies of combined valleys/zones were linked. 5. The much larger River Murray was divided into several valleys. After constructing the valleys, they were then subdivided into zones. These zones correspond to one of seven different categories: Montane, Upland, Slopes, Lowland, Upper, Middle, Lower and Mt Lofty. Four of these zones are based on altitude boundaries as below: Lowland (<200m above sea level) Slopes (200-400m above sea level) Upland (400-700m above sea level) Montane (>700m above sea level) However as three valleys (Lower Murray, Lower Murray and Darling) are fully within the <200m category, other criteria were used to develop zones. This resulted in zones which are defined as pseudo geormophology zones: Upper, Middle, Lower and Mt Lofty. Descriptions of each of these zones is unique to each valley and held in tblzone in the SRA database. Although seven zones have been identified, the number of zones in each valley will vary.在构建SRA河谷分区的过程中，研究人员首先以澳大利亚水资源委员会（Australian Water Resources Council, AWRC）的汇水图层为基础，划定了23个SRA河谷，并依据以下原则进行调整：1. 尽可能沿最高海拔区域（山脊）划定河谷边界；2. 划定河谷边界时，应尽可能避免以河道与州界作为边界依据（即"单河原则"）；3. 水文、气候、地貌差异显著的大型区域不得合并；4. 合并后的河谷/分区的水文系统应保持连通；5. 规模更大的墨累河（River Murray）被拆分为多个河谷。完成河谷划定后，再将各河谷细分为分区。这些分区共分为7类：山地（Montane）、高地（Upland）、坡地（Slopes）、低地（Lowland）、上游段（Upper）、中游段（Middle）、下游段（Lower）以及洛夫蒂山（Mt Lofty）。其中4类分区以海拔边界作为划分依据，具体如下：低地（海拔低于200米）、坡地（海拔200~400米）、高地（海拔400~700米）、山地（海拔高于700米）。然而，由于下墨累河（Lower Murray）、下墨累河（Lower Murray，原文存在重复）与达令河（Darling）三个河谷完全属于海拔低于200米的类别，因此需采用其他标准划分分区，最终形成了被定义为伪地貌分区的4类分区：上游段、中游段、下游段以及洛夫蒂山。各河谷对应的分区描述均具有唯一性，并存储于SRA数据库的tblzone表中。尽管已划定7类分区，但每个河谷实际包含的分区数量并不统一。