Wisconsin Administrative Code › Department of Natural Resources › NR 300-399 - Environmental Protection - Water Regulation › Chapter NR 328 - Shore Erosion Control Structures In Navigable Waterways › Subchapter I - Shore Erosion Control Structures on Inland Lakes and Impoundments › Section NR 328.08 - Data requirements and site assessment methods

Current through June 24, 2024
Applicants and department staff shall adhere to the
					 following data requirements and site assessment methods:
(1) CALCULATION OF STORM-WAVE HEIGHT. The
				  department shall provide applicants with worksheets and internet-based computer
				  software for the purpose of estimating storm wave height. Computer software
				  shall be mathematically designed based on Young and Verhagen (1996) and Young
				  (1998). Storm-wave heights shall be estimated according to Young and Verhagen
				  (1996) and Young (1997) by applying a storm wind speed of 35 miles per hour
				  (51.45 ft/sec), fetch at the applicant's shore protection site, and the average
				  depth along that fetch. To record fetch, applicants shall measure the longest
				  unobstructed straight-line distance originating from the shore protection site
				  across the water surface to the opposite intersect with the shore. To estimate
				  average depth applicants shall examine a lake map, sum the reported depths
				  along the fetch, and divide by the number of recorded values. At least 5
				  equally placed intervals along the fetch shall be used.
Note:
The citation for Young (1997) is as
					 follows: Young, I.R. 1997. The growth rate of finite depth wind-generated
					 waves. Coastal Engineering, Vol. 32, pp. 181-195. The citation for Young and
					 Verhagen (1996) is as follows: Young, I.R. and L.A. Verhagen. 1996. The growth
					 of fetch limited waves in finite water depth. Coastal Engineering, Vol. 29, pp.
					 47-78.
Note:
Statewide storm wind speeds are
					 estimated from Naber Knox, P. 1996. Wind Atlas of Wisconsin. Wisconsin
					 Geological and Natural History Survey, Bulletin No. 94.
(2) CALCULATION OF EROSION INTENSITY. Where
				  an applicant or the department believes that, as a result of site conditions,
				  storm-wave height as calculated in sub. (1) may inaccurately predict the degree
				  of erosion, the erosion intensity score may be calculated to determine erosion.
				  The department shall provide applicants with worksheets and internet-based
				  computer software for the purpose of calculating erosion intensity. When the
				  department or applicants assess erosion at the shore protection site, they
				  shall apply methods outlined in Table 1 to calculate an erosion intensity
				  score. Wherever EI and storm-wave height result in different energy categories,
				  the site shall be placed in the category as determined by EI.
(3) BANK EDGE RECESSION MEASUREMENTS. Methods
				  of measuring bank edge recession shall include all of the following:
				  establishment of a physical measurement reference line between at least 2
				  headstakes; date-imbedded photographs showing the initial installation of the
				  reference line and headstakes; reference distance measures to the bank lip
				  shall be reported on department supplied forms; and time between separate
				  measurements shall equal or exceed 3 months during the open-water season.
Table 1
Erosion Intensity (Ei) Score Worksheet
Applicants and department staff shall use this worksheet to
					 calculate erosion intensity pursuant to s. NR 328.08(2).
SHORELINE VARIABLES
DESCRIPTIVE CATEGORIES
Erosion Intensity Value is Located in Parenthesis
								  on Left Side of Each Category Box
ASSIGNED
EI
AVERAGE FETCH1-
								  average distance (miles), across the open water to the opposite shore measure
								  45° other side of the perpendicular to the shoreline.
(0) <1/10
(2) 1/10 -1/3
(4) 1/3-1
(7) 1 -3
(10) 3-10
(13) 10-30
(16) >30
DEPTH AT 20 FEET, depth of water (feet) 20 feet
								  from shoreline
(1) <1
(2) 1-3
(3) 3-6
(4) 6-12
(5) >12
DEPTH AT 100 FEET, depth of water (feet) 100 feet
								  from shoreline
(1) <1
(2) 1-3
(3) 3-6
(4) 6-12
(5) >12
BANK HEIGHT 
								  2, height of bank (feet),
								  measure from toe of the bank to top of the bank-lip.
(1)<1
(2) 1-5
(3) 5-10
(4) 10-20
(5) >20
BANK COMPOSITION
composition and degree of cementation of the
								  sediments
(0) rock, marl, tight clay, well cemented sand
								  (dig with a pick)
(7) soft clay, clayey sand, moderately cemented
								  (easily dug with a knife)
(15) uncemented sands or peat (easily dug with
								  your hand)
INFLUENCE OF ADJACENT STRUCTURES,
likelihood that adjacent structures are causing
								  flank erosion at the site
(0) no hard armoring on either adjacent
								  property
(1) hard armoring on one adjacent property
(2) hard armoring on both adjacent
								  properties
(3) hard armoring on one adjacent property with
								  measurable recession
(4) hard armoring on both adjacent properties
								  with measurable recession adjacent to both structures
AQUATIC
								  VEGETATION3
type and abundance of vegetation occurring in the
								  water off the shoreline
(0) rocky substrates unable to support
								  vegetation
(1) dense or abundant emergent, floating or
								  submerged vegetation
(4) scattered or patchy emergent, floating or
								  sub-mergent vegetation
(7) lack of emergent, floating or submer-gent
								  vegetation
BANK VEGETATION,
type and abundance of the vegetation occurring on
								  the bank face and immediately on top of the bank lip
(0) bank composed of rocky outcropping unable to
								  support vegetation
(1) dense vegetation, upland trees, shrubs and
								  grasses, including lawns
(4) clumps of vegetation alternating with areas
								  lacking vegetation
(7) lack of vegetation (cleared), crop or
								  agricultural land
BANK STABILITY, The degree to which bank and
								  adjacent area (within 10 feet of the bank-lip) is stabilized by natural ground,
								  shrub, and canopy vegetation (outside a 10' pier access corridor). Human
								  disturbance is typified by tree removal, brushing, mowing, and lawn
								  establishment.
(0) established lawn with few canopy trees
(1) established lawn with moderate to dense
								  canopy trees
(4) moderate to dense natural ground vegetation
								  and canopy trees with shrub layer substantially reduced; or few canopy trees
								  with moderate to dense natural shrub layer.
(7) moderate to dense canopy trees with moderate
								  to dense natural shrub layer; or other natural features prevents establishment
								  of vegetation.
SHORELINE GEOMETRY
general shape of the shoreline at the point of
								  interest plus 200 yards on either side.
(1) coves or bays
(4) irregular shoreline or straight
								  shoreline
(8) headland, point, or island
SHORE
								  ORIENTATION4
geographic direction the shoreline faces
(0) < 1/3 mile fetch
(1) north to east to south-southeast
								  (349°-360°, 1°-168°)
(4) south to west-
southwest
(169°-258°)
(8) west to north-northwest
								  (259°-349°)
BOAT WAKES5
proximity to and use of boat channels
(1) no channels within 100 yards, broad open
								  water body, or constricted shallow water body; or channels within no-wake
								  zones
(6) thoroughfare within 100 yards carrying
								  limited traffic, or thoroughfare 100 yards to % mile offshore carrying
								  intensive traffic
(12) thoroughfare within 100 yards carrying
								  intensive traffic (unregulated boating activity)
EROSION INTENSITY SCORE (EI)
Note:
Table 1 is adapted from Knutson, P. L.,
					 H. H. Allen, and J. W. Webb, 1990. "Guidelines for Vegetative Erosion Control
					 on Wave-Impacted Coastal Dredged Material Sites, "Dredging Operations Technical
					 Support Program Technical Report D-90-13,U.S. Army Engineer Waterways
					 Experiment Station, Vicksburg, MS 39180, 35 pp.
1 Average fetch: The following diagram describes the
					 calculation of average fetch.
See
								  Image
2 Bank height: The following diagram describes the features
					 of the bank for the purpose of accurately measuring bank height
See
								  Image
3 Aquatic vegetation: Dense or abundant means that on
					 average 50-100% of the bottom is visually obstructed by plants during the
					 growing season, defined by the dates June 1 through September 15. Scattered or
					 patchy means that on average 1-49% of the bottom is visually obstructed by
					 plants during the growing season, defined by the dates June 1 through September
					 15. Absent means that on average < 1% of the bottom is visually obstructed
					 by plants during the growing season, defined by the dates June 1 through
					 September 15.
4 Shoreline Orientation: The following lake map shows an
					 example of accurately determining shoreline orientation
See
								  Image
5 Boating: A thoroughfare is identified as physical
					 narrowing of the waterbody that by its nature intensifies boating activity near
					 the shore. Thoroughfares which are 250 yards or wider are not scored 12 points,
					 unless the depth contours of the thoroughfare constricts boating activity in
					 close proximity to one shore, and the traffic is intensive. Intensive traffic
					 is defined by a location where at least 50% of the public boating access
					 available must pass through the thoroughfare to reach the open water of the
					 lake, provided the waterway has a total of more than 60 car-trailer units.
					 Limited traffic is defined by a location where at least 30% of the public
					 boating access available must pass through the thoroughfare to reach the open
					 water of the lake, provided the waterway has a total of more than 40
					 car-trailer units.