The natural vegetation of the Hay River catchment is predominantly forest with a great range of forms and diversity of species. Throughout the area there are also broad swampy drainage lines which carry paperbark or banksia woodlands. Approximately 70% of the catchment has been cleared for agriculture.

The headwaters of the River begin just north of Mount Barker and eventually flow into the Wilson Inlet.

The Mitchell River is a tributary to the Hay River and joins the Hay River 10 kilometres upstream from South Coast Highway crossing. The Mitchell River catchment is pristine condition is located in the Mount Lindsay National.

The River was sampled between June and September 2007.

Only sites HAY03, HAY08, HAY13, HAY16, MIT01, MIT02 and MIT03 were sampled for fish species. Western Minnow were recorded at all sites apart from HAY16 and MIT03. Mud Minnows and Night Fish were recorded at sites HAY08, HAY13, MIT02 and MIT03. HAY08, HAY13, MIT01 and MIT03 all recorded Western Pygmy Perch.

Two fresh water crayfish species (Cherax preissii and Cherax crassimanus) were recorded in the both the Hay and Mitchell Rivers.

Pictures of these can be viewed in the gallery.

All sites on the Mitchell River, HAY08, HAY09, HAY10, HAY12, HAY13 and HAY18 were considered to be in A grade condition. HAY03, HAY04, HAY05, HAY14 and HAY19 are B grade condition and the remaining sites are in C grade condition.

HAY01 and HAY10 were not sampled for water quality.

All sites on the Mitchell River, HAY13 and HAY17 recorded fresh water levels of conductivity. HAY03, HAY06 - HAY09, HAY11 - HAY14, HAY18 and HAY19 all recorded brackish levels of conductivity and all other sites were saline.

All sites on the Mitchell River, HAY04, HAY05, HAY12, HAY13, HAY14, HAY16 and HAY18 had an acidic pH levels between 3.8 and 6.48. All other sites were neutral.

MIT02, HAY11, HAY13, HAY15, HAY18 and HAY19 all recorded low level of turbidity. Very high levels were recorded at MIT01, HAY02, HAY03, HAY05, HAY07 and HAY14. All other sites recorded moderate or high levels of turbidity.

The level of total phosphorus recorded at all Mitchell River sites, HAY07, HAY08, HAY09, HAY15, HAY16, HAY17 was low. Moderate levels were recorded at HAY03 and HAY19. No other sites were sampled for total phosphorus.

Sites HAY02, HAY05, HAY06 and HAY08 all recorded moderate levels of total nitrogen and HAY03, HAY07, HAY17 all recorded high levels. Sites HAY13 and HAY15 were not sampled and all remaining sites recorded low levels of total nitrogen.