Step 1: Check statement I against the definition used in soil conservation engineering. Soil and water conservation is indeed the set of measures for control of water erosion plus conservation of rainwater and moisture, so statement I holds.
Step 2: Check statement II independently using the slope erosion relationship. Erosion rate increases sharply with slope steepness because of higher runoff velocity, so hilly regions naturally show severe erosion, confirming statement II.
Step 3: As neither statement contradicts known conservation engineering principles, both must be accepted together.
\[\boxed{\text{Both Statement (I) and Statement (II) are correct}}\]