11 ATTACHMENTS 9 -16 - Laserfiche WebLink

discussions, Staff has proposed using a topographic drawing with 2' contour lines and then use a single contour line to determine slope which is a 2' rise over an 8' run. I have pointed out such a fine measurement isn't very practical because a single contour lines are not that accurate and small features could create areas of slope greater than 25% which would require Staff make a discretionary decision. Staff opines in this report on page 12 that slope is defined as a"nominal"value not an average. Unfortunately this statement is incorrect, all measurements of slope are by definitions are averages because it is division of the sum of interval of a length by the sum of the interval length it is a mathematical average. I have suggested a more useful measure is using a 10' rise over a 40' run using a topographic drawing which has 2' contour lines. This would smooth small features and is feasible to measure on a topographic plot. The key point is it would eliminate the need for discretionary decisions by Staff. I have proposed a measurement criteria to Staff of "Grading or construction of structures is prohibited on slopes measuring greater than 25%on parcels where the lowest point to the highest point on the parcel is greater than 50 vertical feet. Exempt from this policy are housing developments of 10 or fewer housing units on a single property that was, as of January 1, 2007, "legal parcel" pursuant to the California Subdivision Map law. The slope percentage of each area of a parcel shall be calculated by dividing the natural vertical rise (in feet) by an underlying forty foot (40) horizontal run (rise in feet/40' = %of slope) at every 2 foot contour line. The measurements shall be taken perpendicular to the center-most contour line of the horizontal run. All areas on the parcel proposed for structures or grading which exceed the 25%slope as defined above shall be marked with color or hatched pattern on a topographical map of 2'contours with a minimum scale of 1" =80'. " It is important to note that no matter which length is used for the measurement criteria, the same formula is used to calculate the slope and if the results are greater than 25% than it is a violation of PP. My concern with Staff's proposal is that it requires discretion on where PP should apply which allows PP to be thwarted. A perfect example of the misapplication of such discretion is the area being proposed to be excluded because of man-made slopes. There is a commentary on pages 16-19 of the Staff report exempting man-made slopes from PP, but as you can see in the text of the initiative,there is no such exemption provided for. Such exemptions cannot be created without going to a public vote. However I don't think that necessary for this project. The actual areas of man-made slopes are a small portion of the area marked on Fig 7 slope map as drawn by the developer.Apparently a small road cut and cut for a pad for barn is being used to justify developing a far larger area with natural slopes greater than 25%. For the small areas of modified slopes, Staff suggests that original slope contour should be used rather than the modified slope. However the original slope as highlighted by Staff is greater than 30%. The unmodified slope above Staffs redline is greater 25%as well. I have included the photo from the Staff report below and I have added the black text. This area does not benefit from using the original slope. The measurements can be verified by