>>2833902
In rainy season, the rivers all turn brown (almost all) and double, triple or more in volume. In the dry season, they run clear, even the Mekong. There are beaches in the Mekong, especially in southern Laos (4,000 islands) with plenty of sand. The river is full of sand because of erosion. As for leeches I'm guessing they are similar to anywhere else. American rivers and creeks are also full of leeches. If you are in them enough, you will encounter them. The Nam Ngum reservoir has a few "beaches" I think but these are more rocky. It doesn't get much tourism but they built a casino out there recently.
>>2833941
>pile of silt.
Actually, the silt washes downstream into Cambodia, where a lot of it ends up in the Tonle Sap, making Cambodia very fertile and how Angkor was able to emerge as a civilization. The rest goes down into the Mekong Delta, so Laos loses all its silt to the downstream countries. It was never as productive agriculturally for this reason. That, coupled with being landlocked, kept it at a disadvantage.