{"id":3830,"date":"2022-10-27T10:56:14","date_gmt":"2022-10-26T21:56:14","guid":{"rendered":"http:\/\/blogs.lincoln.ac.nz\/gis\/?p=3830"},"modified":"2023-05-07T01:55:46","modified_gmt":"2023-05-07T01:55:46","slug":"orderly-streams","status":"publish","type":"post","link":"https:\/\/blogs.lincoln.ac.nz\/gis\/orderly-streams\/","title":{"rendered":"Orderly Streams"},"content":{"rendered":"

Stream order is a way to categorise river reaches by size.\u00a0 In this post we see how\u00a0to\u00a0add stream orders to a derived stream network.<\/em><\/p>\n

As the temperatures warm up, the tramping season has already gotten underway in our house so keen daughter Islay recently dragged me up the short but steep track to Carroll Hut<\/a> in Arthur’s Pass National Park, just north of Otira of State Highway 73:<\/p>\n

\"\"<\/a><\/p>\n

While we weren’t on the main divide here, we were above treeline and in the area where you could expect to find small headwater streams and the occasional scenic tarn:<\/p>\n

\"\"<\/a>
https:\/\/www.doc.govt.nz\/parks-and-recreation\/places-to-go\/canterbury\/places\/arthurs-pass-national-park\/things-to-do\/huts\/carroll-hut\/<\/em><\/span><\/figcaption><\/figure>\n

One of the things I really enjoy about tramping is that it gives you some time to finally think about a few things, unfettered by the daily stress of the to-do list.\u00a0 This time, my thoughts turned (amongst other things) to streams, and in particular, stream order<\/a>.<\/p>\n

Stream order is a way to categorise streams within a hierarchy of relative size. If you picture the streams in a catchment as all being connected together and building up a linear network, you’re partially on your way.\u00a0 Starting near the catchment boundary, we first encounter order 1 streams, being those headwater streams that seem to start from nowhere.\u00a0 As we move down the catchment, more streams combine\u00a0to become larger rivers, and the order increases.<\/p>\n

As we move down the catchment, these 1st<\/sup> order<\/a> streams join up to make 2nd<\/sup> order streams, which then join up to make 3rd<\/sup> order and up we go.\u00a0 There are a few simple rules that help determine stream order:<\/p>\n