Erosion is overall decreased after these changes. Flattening the steep slope means that water cannot flow downhill. This means that water can't pick up as much sediment. Planting more grass means that the grass and shrubs can absorb more water which decreases runoff and erosion. This also means that the grass and shrubs can hold the soil in place.
First, vegetation reduces runoff by absorbing water and holding soil in place. Second, flat land has less runoff than steeply sloping land. Less runoff generally means less erosion, so the amount of erosion in each yard should be reduced.
I saw both of these on quizlet, hope this helps!
