What is the water quality of the water from the springs as it can be different from the watershed ? Soil sample tests would be a good idea.

What are your goals ? Thirty acres will produce a lot of fish even at low productivity. How many people will be fishing and what do they want ?

If your goal is a good fishery for more than a few people you will need to deal with the alkalinity. No matter what the natural or artificial fertility of the water at that low an alkalinity you will not have much of a plankton food chain base. You could undertake a massive feeding program to avoid the food chain problem but recruitment may be a problem. Stress from ph swings due to low alkalinity will hamper fish growth and survival.

We have springs also with water flow through sometimes 7-8 mths a year at a rate (guess here) avg of 25 gals a min. We lime and fertilize with very good results. Our standing natural alkalinity is about 9 ppm. With lime about 25.