Gasparillo owes much of its size to its proximity to the Petrotrin oil refinery at Pointe-à-Pierre.
The largest petroleum producers in the country - BP Trinidad & Tobago (bpTT), BHP Billiton and Petrotrin all have major presences here and bpTT controls the Port of Guayaguayare, which services most of the offshore petroleum production in Trinidad.
Onshore oil production is under the control of Petrotrin, although a considerable area has been farmed out to small independent oil producers.
Today, Petrotrin operates Trinidad and Tobago's single petroleum refinery, located at Pointe-à-Pierre, just north of San Fernando in south Trinidad.
It is most famous as the site of the country's largest (and now, only) oil refinery which is run by Petrotrin, the state-owned oil company.
The river is heavily polluted, both by non-point agricultural and residential run-off from Marabella and the town of Gasparillo, and from industrial waste (primarily oily run-off) from the oil refinery at Pointe-a-Pierre owned by Petrotrin (the State-owned oil company).