2019 SWCS International Annual Conference July 28-31, 2019 Pittsburgh, Pennsylvania

1. ACPF Version 3: Riparian
Catchments and Applications
MARK TOMER, USDA-ARS

2. New features in ACPF version 3
 Wide rivers and water bodies can be incorporated into the stream network
to enhance riparian/shoreline planning results.
 Riparian catchments – approach to discretize watershed to identify
contributing areas to riparian lengths
 Farm ponds tool

3. August 13, 20193
Wide Rivers Lakes

4. August 13, 20194
PROCESS
1. User provides lake and wide river
polygons
2. Stream reach centerline is erased from
interior of water body polygons
3. Water body polygons are
converted to lines and merged
with stream reach centerline
4. Each unique reach (junction to junction)
is assigned a new LINKNO
5. Optionally, an output water body
feature class can be created
 We are NOT changing the flow routing!
 We are expecting that flow will be routed
“across” the boundary of water body
polygons

5. 1. Identify each stream reach
• Identify path length of each reach

6. 2. Calculate number of
segments along stream reach
• Identify path length of each reach
• Calculate # of segments to be placed
along reach (length specified by user
default of 250 meters)
• 1920.2/250 = 7.68 ~ 8 segments

7. 3. Adjust for sinuosity
• Identify path length of each reach
• Calculate # of segments to be placed
along reach (length specified by user
– default of 250 meters)
• 1920.2/250 = 7.68 ~ 8 segments
• Adjust for sinuosity. Recalculate
length of each segment based on the
proportion of its straight line
distance to the total.
• if all segments were of equal sinuosity,
the proportion of each to the whole
would be 100/8, or 12.5%

8. Original
length of
each
segment
240.02
240.02
240.02
240.02
240.02
240.02
240.02
240.02
Straight line
distance of
each
segment
218.7
210.50
212.5
205.4
165.2
187.3
162.6
182.2
Proportion of
straight line
distance to
total
14.2%
13.6%
13.8%
13.3%
10.7%
12.1%
10.5%
11.8%
Deviation from
proportion if all
segments were
equal sinuosity
(12.5%)
1.7%
1.1%
1.3%
.8%
-1.8%
-.4%
-2%
-.7%
How to divvy up
actual length
12.5-1.7 = 10.8%
12.5-1.1 = 11.4%
12.5-1.3 = 11.2%
12.5-.8 = 11.7%
12.5+1.8 = 14.3%
12.5+.4 = 12.9%
12.5+2 = 14.5%
12.5+.7 = 13.2%
New length
.108(1920.2) = 208.23
.114(1920.2) = 218.3
.112(1920.2) = 215.8
.117(1920.2) = 224.7
.143(1920.2) = 274.6
.129(1920.2) = 247.2
.145(1920.2) = 277.8
.132(1920.2) = 253.5
Total length of reach = 1920.2 meters
1544.4
Less sinuous
More sinuous

9. 4. Find watersheds to each segment, split by stream
Define
Watersheds
to each
stream
segment
Split
watersheds
by stream

10. 5. Assign unique IDs
Each riparian catchment has a unique
riparianid:
29_4_2
• 29 indicates catchment, or reach
• Derived from input stream reach
• 4 is order (1 – n)
• 2 indicates left (1) or right (2) side
• Headwater catchments are specified
as: 29_headwaters

11. Get a more accurate representation of the landscape by
including water bodies and wide rivers
No water bodies Wide river and lakes

12. Land Use, tile
drainage, and
saturated buffer
opportunities

14. Relative N
loading based on
cropping history
and N application
rates typical for
crops in rotation