On and after June 20, 1956, in addition to the funds available under the appropriation “Rio Grande emergency flood protection”, the United States Commissioner is authorized to expend from any appropriation available to the International Boundary and Water Commission, United States and Mexico, American Section, such sums as may be necessary for prosecution of emergency flood fighting and rescue operations, repairs or restoration of any flood control or sanitation works threatened or destroyed by floodwaters of the Rio Grande, the Colorado or Tijuana Rivers, or other streams running across or near the boundary, and for taking emergency actions, consistent with the emergency provisions of the Safe Drinking Water Act [42 U.S.C. 300f et seq.], to protect against health threatening surface and ground water pollution problems along the United States-Mexico boundary.