Groundwater & Basement Water Intrusion in Clive, IA

That is answered by elevation rather than by distance. The greenbelt is a floodplain doing its job, and what matters is where your finished floor sits relative to where the water spreads in a large event. Two houses the same distance from the trail can be very differently exposed. Knowing your own elevation, and what the creek has done in past large storms, predicts far more than proximity does.

That is normal here and it is worth checking the discharge anyway. Loess absorbs a great deal and then releases it slowly, so the tile keeps feeding the pit long after the rain stops. What is not normal is a pump that never rests even in dry weather, which usually means the discharge line ends too close to the house and the water is circulating back into the same ground the tile drains.

It is something to understand rather than worry about. It takes water in well, which is good, and it loses strength when saturated, which means backfill against a foundation can settle after a long wet spell and open a channel down the wall. Checking and topping up settled backfill after a wet year is a specific and useful habit here in a way it would not be on stable clay.