Which preposition to use with pasig

to Occurrences 3%

Ibarra's escape had been effected by Elias, who conveys him in a banka up the Pasig to the Lake, where they are so closely beset by the Civil Guard that Elias leaps into the water and draws the pursuers away from the boat, in which Ibarra lies concealed.

at Occurrences 1%

According to the report of an engineer, the sand banks are caused by the river San Mateo, which runs into the Pasig at right angles shortly after the latter leaves the Lagoon; in the rainy season it brings down a quantity of mud, which is heaped up and embanked by the south-west winds that prevail at the time.

in Occurrences 1%

Tomorrow 7.15 Pasig in our power.

Which preposition to use with  pasig