Could this be Hestia (1979) by C.J. Cherryh...?
From Wikipedia:
Hestia is a 1979 science fiction novel by American writer C. J. Cherryh. It is an early novel in her career, about colonists on an alien world and their interactions with the catlike natives, centering on a young engineer sent to solve the colonists' problems, and his relationship with the young native cat-woman in scanty clothing on the cover.
From a review:
Sam Merritt is a young and ambitious Federation engineer who decides to participate in a project on the Earth-like planet Hestia. Unfortunately, when Sam arrives he discovers that the dwindling human colony on the planet possesses only a late 19-century level of technology, and what outposts still survive are rustic at best.
Needless to say anti-gravity lifters, nanobots, and laser drills are not available, much less mechanized bulldozers, pile drivers, and front-end loaders. Sam tries to skip out on his contract, but finds himself shanghaied into service by the desperate Hestians: with most of population crammed into a river valley subjected to periodic floods, a dam must be constructed upstream to save the human civilization. Indeed, if the dam is not built within the span of a year, it's possible a flood could convert most of the planet's agricultural landscape into a swamp.
Sam travels upstream to the dam site and gradually discovers something the colonists are reluctant to talk about: there are aboriginal Hestians, referred to as ‘The People’, living in proximity to the site, and they don’t like the idea of constructing a dam on their territory.
As the struggle to build the dam proceeds, Sam befriends one of the natives, Sazhje, the cat-girl from the cover. This does not endear him to the human colonists. Soon the violence between aborigine and colonist escalates, and Sam finds himself distrusted by both sides. Can he prevail with construction of the dam, or will the enmity between the races lead to its destruction and ethnic warfare ?