ECHO SUMMIT (AP) — The water content of the Sierra Nevada snowpack in drought-stricken California was 136 percent of normal Wednesday when officials took the winter’s first manual survey — an encouraging result after nearly no snow was found at the site in April.The latest snow level is a good sign, “but that’s it — it’s a start,” said Frank Gehrke, chief of the California Cooperative Snow Surveys Program for the Department of Water Resources.After four years of drought, Gehrke plunged a measuring pole into a thick field of snow in the Central Sierra, which includes Lake Tahoe. His survey followed an electronic measurement last week that put the water content of the snowpack at 112 percent of normal. Even more snow has fallen since then.The snowpack provides about 30 percent of California’s water supply during the months when it melts and rushes through rivers and streams to fill reservoirs that remain critically low.Last Jan. 1, the snowpack was a meager 45 percent of the historical average.