Where I Find The Most Gold Nuggets
Easier to access prospecting locations are unlikely to have significant yields of gold nuggets for obvious reasons, and it can also be difficult to find productive areas within even remote rivers and streams that have a significant yield. As with most endeavors, a less common and more difficult approach to prospecting can result in a greater reward. These areas are also often inaccessible for a significant portion of the year, and require favorable weather conditions to be workable. I am operating on the assumption that you already have the basic knowledge of entry level prospecting: locating areas where gold nuggets are likely to accumulate, panning, sluicing, etc.
Waterfalls and smaller falls typically have large pools of water below them. While the larger ones are inaccessible to everyone other than professional divers (and some aren't at all), the smaller ones offer possibilities for prospecting. Rivers and streams typically run along bedrock, and it is in the depressions of the bedrock where gold nuggets accumulate. We know that the flow of water over many years causes depressions in the bedrock, but little consideration is given to the fact that heavy flows of water also move rocks over falls; these rocks then strike the bedrock below the falls, causing a much larger depression than we may realize.
If you can locate such a fall, or series of falls, in a stream that is known to have at least yielded some gold, the chances of there being a significant amount in the pool or depression are very high. Such falls are usually flowing fairly well most of the year, and are either too deep or running too strongly for you to safely prospect in them. Even at their slower flow rates, the water running from snow melts or cold rain in the mountains makes them difficult to work without hip waders, long rubber gloves, and possibly even rain gear. Depending on the amount of rainfall, they may be accessible during part of the summer. However, you may also be able to work them between winter and fall if the rainfall has been minimal: or when it first starts to freeze in the mountains. Many of these will actually cease to flow entirely in the right conditions, and you should be prepared to take advantage of the situation. You may have to wait a few years for the conditions to be right, but you should not forget the possibilities that such a location would have.
While it is typically wise to avoid using a dredge pump along with your sluice box unless you are finding enough gold to warrant packing heavy equipment long distances through the woods, you should probably make the extra effort if the amount of material you can potentially work in the pool or pools is more than you can do by hand. Any significant rainfall is likely to take away your window of opportunity, and it is in the cracks of the bedrock of these pools that gold nuggets are most likely to be found. If you are able to remove enough material to get to these cracks, you will need the dredge pump to suck the gold nuggets from them.
It is in these pools where I find most of my gold nuggets, and it is also an operation that I will not undertake without a partner. Keep in mind that these areas are slippery and dangerous, and that there may be enough current to push you over a lower fall or simply cause you to strike your head on a rock. If the safety of an operation is questionable, leave the gold for someone else.