From that point river also changes its name, appropriately, to the Prokop, which in English literally translate as a trench, a ditch or dug out canal.

After 14.9 kilometers the Bistrica than receives significant amount of waters from northwestern half of Livanjsko Polje, which is channeled through artificial canal named after existing river, the Plovuča, which still exists in that part of the polje (English: field).

At 20.3 kilometers the Bistrica finally reaches Lipsko Lake, near village of Lipa, which is first and smaller of two artificial reservoirs in hydroelectric power plant system Buško Blato - HE Orlovac, other being Buško Blato reservoir.

In this system Lipsko Lake is a compensation basin and serves for regulation of an outflow of water toward intake facility at penstock station "Lipa" at the foot of Kamešnica mountain, and across the border into Croatia where hydroelectric power plant "HE Orlovac" is situated.

Lipsko Lake is connected with much larger reservoir of Buško Blato, whose head can rise above head of Lipsko Lake up to several meters, via the reversible canal of "Lipsko-Buško" where it stores an excess waters from Livanjsko Polje and the Bistrica, especially during flooding season and high precipitation periods.