Refer to Section A–A. A park district wants a scenic overlook with an unobstructed view of the whole lake surface, measured from ground level. The overlook must be outside the 100-year floodplain (elevation 28). Select the location.
Click the correct area of the figure.
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Answer: C
- Point 2 to the near shore: from (station 190, elev. 80) to (station 510, elev. 20), the line drops 60 over 320 units.
- At the ridge (station 370): 80 − 60 × 180 ÷ 320 = 46.3 < 70, so the view is blocked.
- Point 3 to the shore: from (370, 70) to (510, 20), the line is at 45 at station 440 (ground 40) and 27.1 at station 490 (ground 24), so it is clear.
- Point 4 (elev. 24) is below the 28 flood elevation.
Circle at Point 1: At elevation 50, the view east is blocked by the 80 hilltop and the 70 ridge.
Circle at Point 2: It is the highest point, but the sight line to the lake shore falls to about 46 at the ridge (station 370), which is below the ridge top at 70, so the ridge hides the lake.
Circle at Point 3: Correct. From the 70 ridge the ground falls in a concave slope to the shore, so the sight line clears the terrain to the whole lake, and the point is well above flood elevation 28.
Circle at Point 4: It sees the lake, but at elevation 24 it lies below flood elevation 28, inside the floodplain, which breaks the stated constraint.
In a visual resource analysis, check sight lines on a section: an intervening high point blocks the view whenever the straight line from viewer to target passes below it. The site must also meet every non-visual constraint.