LAS VEGAS — Government officials from United States and Mexico have made a Tuesday date in San Diego to sign a landmark agreement to share Colorado River water during times of drought and surplus.The time and place were confirmed Friday by International Boundary and Water Commission official Gustavo Ramirez. The commission’s U.S. section secretary, Sally Spener, said this week from El Paso, Texas, that there were still a number of reviews and approvals needed north and south of the border before the addendum to a 1944 U.S.-Mexico water treaty is signed.The Southern Nevada Water Authority and Colorado River Commission of …