Low-income people could get veterinary treatment for their pets in a proposed expansion of the Humane Society for Southwest Washington clinic, according to a plan outlined Thursday.A capital campaign seeks to raise $9.8 million for construction and endowments with a target of starting construction of the 12,000-square-foot project in early 2020, and finishing later that year. Already $3 million has been pledged by an anonymous Clark County resident. Project planning has been underway for about two years, said the nonprofit’s president, Stacey Graham, who announced the project Thursday at the society’s annual luncheon. The clinic, to be built onto the existing building in east Vancouver, would fill a growing need for pet care in the region, Graham told the audience.The clinic — which would charge a sliding fee scale with an average of $75 a visit — would allow approximately 4,300 animal to be treated a year. At the same time, the Humane Society plans to partner with 10 veterinary clinics in Clark, Cowlitz and Wahkiakum counties to handle 1,500 additional pet visits by low-income pet owners.