What is the total Design flow (LPM) with a Partner of app, a Construction Start of 2008 january, and a Population Served larger than 3500?
CREATE TABLE "plants" (
  "location" text,
  "partner" text,
  "construction_start" text,
  "inauguration_date" text,
  "population_served" real,
  "design_flow_lpm" real
);
SELECT SUM("design_flow_lpm") FROM "plants" WHERE "partner"='app' AND "construction_start"='2008 january' AND "population_served">3500;