What are wet and dry gold diggings?

Trinity River CA

In the early days of the gold rush miners worked the gravel bars and streambeds where water to wash the gold from the ore was plentiful and readily available. But soon some of the richest deposits were found in ravines that only carried water during the rainy season or, in some cases, on high slopes or elevated flats where there was no water at any time. The first miners had to carry the gold bearing ore to a steam or wait for the onset of winter rains to process their gold. These places were known as dry diggings in contrast to those along the streams where water was abundant which were called wet diggings.

In some situations, where water was not readily available by any means, miners would resort to a technique taken from the Sonoran miners who came up from Mexico. Called dry washing it was similar to the old process of winnowing wheat. Here ore was dried completely and the pebbles and rocks picked out. The rest of the finer particles were repeatedly tossed into the air on a windy day, allowing the lighter sand and dirt to blow away while the heavier gold could easily be recovered. But all the dry mining techniques were abandoned as soon as ditches and flumes provided water to almost every operation in the gold country.