Your seadoo needs at least 12" of water to float. Remember at an idle it is still pulling in water, and any thing it can get it's grasp on, through the jet pump. The safest real depth is 2', but if it has a hard bottom you could sneak through a depth of 1.5, just be sure to stay at an idle, and for users of 2 engines use one engine to reduce the amount of water draw. 2 engines will draw more turbulence from the bottom. Keep an eye on your wear rings clearance too, as they may tend to wear out quicker with more debris being drawn through them. Sand usually plays a scuffing affect on the plastic wear ring so it will wear faster. I live in Florida where we only have sand and shallow waters, that's why I bought a seadoo. I do go through wear rings quicker than most users, but it's a small price to pay for boating when the water gets low in the winter months and all my buddies with stern drives, "Prop" driven boats, are watching me go boating while they wait for high water in our tide controlled water ways.
Karl