The following text is related to groundwater rights compromised between the city of Ft. Collins and North Poudre Irrigation Co. It discusses how much right each one has for taking water ground.

This depletion would normally give rise to a “call on the river” whereby the North Poudre Irrigation Co. is required by the Office of the Colorado State Engineer to cease groundwater pumping operations since they are damaging the senior surface water rights owned by the City of Ft. Collins.

What is the meaning of "Call on the river" as stressed?

The following text is related to groundwater rights compromised between the city of Ft. Collins and North Poudre Irrigation Co. It discusses how much right each one has for taking groundwater.

This depletion would normally give rise to a “call on the river” whereby the North Poudre Irrigation Co. is required by the Office of the Colorado State Engineer to cease groundwater pumping operations since they are damaging the senior surface water rights owned by the City of Ft. Collins.

What is the meaning of "Call on the river" as stressed?