Hi Ken; Welcome to Permies!
Brian ,covered the basics for you let me see if I can expand some on that.
I have been living with micro hydro for over 20 years and I have been off the power grid since 1983.
I'm a little confused about your setup )(lol normal for me) You have a good year round spring on top of a hill and you are clearing its path or a path thru the brush down to your campsite ?
You have a 1000 gallon tank somewhere , I think at the bottom??? This needs to be on top of the hill to be helpful in making power.
Your wondering how much power might be available?
Is there a house ? Or just a tent/ camping spot ?
Brian headed you in the right direction, we need numbers.
To start we need a distance from the top of the hill to your spot., Next is this spot directly downstream or off on a tangent? (i.e.) Can the waste water from the hydro easily get back into the stream ???
You MUST have a way for your unpressurized waste water to go away. The amount of fall can be determined by pressure. The amount of flow needs a pipe to determine.
Piping your water downhill for a hydro is not as straight forward as just supplying drinking water. Hard white pvc has external connectors that do not slow the flow. It must be carefully installed properly bedded or it will crack. Black Poly pipe is much more commonly used, it can be tossed in a shallow ditch and avoid obstacles that a ridged pipe can't. It has internal connectors , these will catch debris over time and they will plug up. (I have to use a large diesel air comp almost every year to blow mine backwards to clear it) I have 2200' of line with 300' vertical drop.
Depending on the distance it has to travel, water running thru enclosed lines experiences "line loss" (that is friction inside the line). Literally if you took a 1/2" line and tried running it down hill after a unknown distance it would just stop flowing !!! Amazing. To defeat this you need larger lines. Mine is 1.5" . It can also be defeated by changing line size part way down hill. (i.e.) start with 1' go 150' change to 1.25 " go another 150' switch back to 1" ... this eliminates the friction effect.
O.K.) So we have now piped water at the bottom , we have a place for that water to go after it runs thru the hydro. Flow can be determined with a 5 gal bucket
or a 55 gal barrel no matter. You need to know how much water is up on top of the hill. It may look like a lot but might be easy to overrun. This is what the flow rate will tell you. My spring is a high head low flow. Lots of pressure 125 psi at the house, but I can only pull apx 3-4 gal per minute or I start draining the 400 gal tank and the then line ...eventually I see a power loss down below.. The best hydro would be high head high flow , possible you have that but it is more likely you are in the middle.
On to hydro units, I use a Harris permanent magnet hydro with a stainless steel pelton wheel. Grit coming down line ate up the bronze wheels that most hydro's come with. Harris hydro has been around a very long time, they certainly are not the only manufacturer of micro hydro's but are probably one of the most used . I recommend it. Micro hydro's come with nozzel options, 1 to 4 nozzels spraying water at your pelton.This is why you need flow information to choose the correct size unit to order.
Location) I see you were hoping for your hydro to be on top of the hill... not fesable... unless its a river and you produse A/C power not D/C ) Thats also not happening or you would need to register your hydro with the federal goverment. They ignore micro hydro D/C .. but they want a cut if you are making mucho A/C power off of "THEIR" water. A/C power can be transmited long distance with small wire and minimal loss...D/C power must be right there or you could not get large enough
wire to transmit it long distance.
Now this is IMPORTANT) A hydro must ALWAYS be connected to a battery bank or it will over voltage itself and fry in short order!!! There is NO avoiding this! It must ALWAYS be connected. A solar
set up can be disconnected anytime with no issues . Solar charge controlers maintain battery voltage by conect / disconect cycles . This would fry a hydro in less than an hour. For hydro power and for wind power you must use a constant diverion charge control and have a place to dump up to 95 % of all your power prodused without disconecting from the hydro....
I hope I haven't overloaded you with info or worse that I scared you off from investigating the possabilitys. Making your own power is very liberating, its a wonderful thing when your home is lit up while all your neigbors are not...and NO POWER BILL is very cool!
I know a lot about this , if you have more specific question feel free