The last few kilometres of the Cotter below the dam wall to the Murrumbidgee at Casuarina Sands, open water under the ACT rules, with the Cotter's recreation sites along it and the big river's cod and golden perch a short walk away.
Below the wall of Cotter Dam the river has only a few kilometres left before it meets the Murrumbidgee at Casuarina Sands, and the territory treats that last run as open water rather than trout water. It is the most visited piece of the Cotter, with the campground, Cotter Bend and Cotter Avenue along it, and it is the one part of the river where the open-water rules apply.
The shape is a tailwater from the dam to a junction, and its flow is whatever the dam releases.
What you can expect to catch here is not on record in this guide: the trout water is upstream, and the natives are in the big river a short walk away. Treat it as a place to look at the water, to walk down to the Murrumbidgee, or to fish on the open-water rules if you see a reason to.
The rules are the open-water set: up to two rods or handlines at once with a landing net, no more than two hooks, two flies or one lure on each rod, and you must stay within ten metres of your gear and keep it in sight.
If you came for trout, drive up to the stretch below Bendora Dam. If you came for cod, walk to the Murrumbidgee.