[5] From west of the Coquihalla Lakes[6] on the northeastern slopes of the North Cascades, the river flows northeastward, before entering the Nicola at Merritt.

[11] Along the cobble-bedded, irregularly meandering river, abandoned channels have created low-lying areas of wetland.

On entering the Coldwater Valley bottom, the region changes to the drier Ponderosa Pine/Bunch Grass Zone.

[7] The route includes the Coldwater River Park (near Juliet)[10] and only one canyon (7-kilometre (4 mi) length, north of Brodie).

[27][28] In 1848 and 1849, the Hudson's Bay Company (HBC) tried a new Kamloops–Yale trail, which was ultimately rejected as overly arduous and hazardous.

[29] Developed during 1872–1876, a 2-metre (6 ft) wide upgraded cattle trail, which connected Hope and Merritt via the Coquihalla Pass, was destroyed in the 1910s by the Kettle Valley Railway (KV) construction.

[30] In 1910, a new wagon road was built along the Voght Valley,[31] which included the corresponding part along the east shore of the Coldwater from Merritt.

On fracturing, the pipe leaked crude oil, which was contained behind a quickly prepared earth dam.

During repairs, the greater part of the 950,000 litres; 250,000 US gallons (210,000 imp gal) of released oil entered the dam, but none reached the river.

[46] The Trans Mountain Expansion Project route was revised in 2021 when the Coldwater Band claimed that the original proposal might potentially damage the reserve aquifer.

The change added about 4 kilometres (2 mi), necessitated two crossings of the Coldwater River where none were needed before, and raised further concerns about the local environmental impact.

[54] During the 2021 Pacific Northwest floods, the river damaged the Merritt wastewater treatment plant, about 600 residences, and several commercial properties.

[55] Upstream, workers were able to save the highway bridge at Brodie by dumping rock to protect an abutment.

[56] Along a 30-kilometre (19 mi) stretch south of Merritt, the 14 exposed sections of the existing oil pipeline cost tens of millions of dollars to repair[57] and route revisions were required for the expansion project where river channels had altered.