Mrs. Sinden, 91, a hydrologist in the 1980s for the Delaware River Basin Commission in Trenton, died Wednesday, Nov. 6, at Pennswood Village, a retirement community in Newtown, Bucks County, where she had lived since 1999.
Born in Bethlehem, Pa., Mrs. Sinden graduated in 1939 from Liberty High School there and earned a bachelor's degree in physics in 1943 at Duke University, where she was one of the few women in her class, daughter Amy said.
She worked on underwater sound research at the Naval Ordnance Laboratory in Washington until 1950, when she married.
After they had worked for two years at the Army Dugway Proving Ground in Utah, the Sindens lived in Summit, Union County, from 1961 to 1981.
In the 1960s, she helped found the Summit Neighborhood Council, her daughter said, which set up a food cooperative as well as the preschool program, which became the town's Head Start program.
A community activist, she advocated for what is now the 40-unit Glenwood Place complex, completed in 1972 and run by the Summit Housing Authority.
She chaired the social concerns committee at the Unitarian Church in Summit in the 1970s. As president of the League of Women Voters in Summit, her daughter said, she lobbied Trenton for improved public transportation.
She was a member of the International Institute for Religious Freedom and the United Nations Association.
In retirement, she became an observer at the United Nations for the League of Women Voters.
Besides her daughter and former husband, she is survived by a daughter, Rebecca, and four grandchildren.
A memorial service was set for 1 p.m. Saturday, Jan. 11, at the Unitarian Church in Summit, 4 Waldron Ave.
Donations may be made to www.unfoundation.org/honor.
Offer condolences to Amy Sinden at Temple University Beasley School of Law, 1719 N. Broad St., Philadelphia 19122.