November 9, 2005
St. Albans Landscape Modeling Working Group
Phosphorus Transport Pathways
Dairy Cows
Crops & Pasture
Relative Annual P Loads
for Stevens Brook
Base
Flow
Storm
Runoff
Spring
Melt
Direct Barnyard Discharge
???
???
???
Geese Eat & Transport to Bay
???
???
???
Clay
Other
0.5 - 13%
0.5 - 12%
0.1 - 5%
2 - 29%
9 - 63%
2.5 - 36%
Clay
Other
.2 - 3%
.5 - 6%
.1 - 3%
Ag Surface Runoff
Agricultural Soil
Ag Sub-surface Drainage
< .03%
<.09%
<.01%
Forest Runoff & Erosion
<.05%
<.22%
<.08%
In-stream erosion
???
???
???
Developed Soil
Stormwater Runoff & Erosion
.8 – 3.2%
3 – 12 %
1 – 4.5%
Wastewater
Wastewater Discharge
13 - 44%
???
???
Forest Soil
Stream Banks & Bed
Notes:
• Above does not reflect a physically based model.
• Average values were used for all cells of same landuse (see TP concentrations below).
• GOAL: To develop a physically based model using parameter values below.
DIRECT BARNYARD DISCHARGE
1
*2
*3
*4
Parameter/Assumption
Total cows in the watershed
Value
9,600
Percent of cows housed in
barnyards.
Percent of time cows are in
barn/barnyard v. pasture.
Percent of manure captured in
manure lagoon.
Source
Comments
Eco-indicators report
(stocking density 1.1/ha x
9,142 hectares ag land).
NRCS/farmer/UVM
extension estimate?
NRCS/farmer/UVM
extension estimate?
NRCS/farmer/UVM
extension estimate?
WATER FOWL
*5
*6
7
Parameter/Assumption
Number of geese in watershed
Length of time geese reside in
watershed
TP eaten and excreted by geese
(g/goose/day)
Value
Source
Comments
Dick Longway?
Dick Longway?
.45 g P/day
Post et al. 1998.
Conservation Biology 12
(4). p. 910
Please send comments, suggestions, corrections, and feedback to Erica Gaddis: Erica.Gaddis@uvm.edu.
Gund Institute for Ecological Economics, 610 Main Street, Burlington, VT 05405
November 9, 2005
St. Albans Landscape Modeling Working Group
AGRICULTURAL SURFACE RUNOFF AND EROSION
9
Parameter/Assumption
TP concentration (mg/l):
Clay soil
Other soil
Soil test phosphorus
10
Percent soil saturation of P.
*11
Percent of ag lands with cover
crops.
Percent of manure in watershed
applied to fields.
Frequency and estimated dates
of manure application.
Management practices. Are
8
*12
*13
*14
Value
0.2 – 1.9
0.31 – 2.15
100%
April 15
Suggested Source
Comments
Will reduce uncertainty
with monitoring data.
Average value by soil
type using NRCS files?
Average value by soil
type using NRCS files?
NRCS/farmer/UVM
extension estimate?
Guess. NRCS/farmer/
UVM extension estimate?
NRCS/farmer/ UVM
extension estimate?
Group?
there any universal ‘typical’
practices (i.e. tillage) that can be
summarized for this landscape?
Best to report as % of land by soil
type or landuse (corn v. pasture).
TR55 model inputs based
on landuse and soil type.
NRCS soils database.
15
Curve numbers
0-100
16
Soil infiltration, percolation,
porosity, organic matter, %
sand, silt, clay.
Varies.
17
NRCS soils database
Erosion parameters
AGRICULTURAL SUB-SURFACE DRAINAGE
Source
Parameter/Assumption
Value
18
Enright et al. 2003.
Will reduce uncertainty
with monitoring data.
*19
20
21
*22
23
TP concentration (mg/l):
Clay soil 0.1 – .42
Other soil .06 – .08
Tile drained areas are those
with <3% slope, soils in hydro
group D, and pasture, crop or
fallow landuse.
GIS layers.
FOREST RUNOFF
Parameter/Assumption
Value
Suggested Source
Average TP concentration.
0.005 mg/l Hegman et al. 1999.
IN-STREAM EROSION
Parameter/Assumption
TP in stream bank and
sediments
Predict erosion amt. based on
flow and geomorphic condition.
Geomorphic condition indicates
presence/absence and type of
erosion.
Value
Comments
Suggested Source
Comments
Comments
Testing in G. Druschel’s
lab.
Developing model
derived from WEPP.
Other suggestions? ANR,
River Management
Map of geomorphic
segments. Need data on
condition by segment.
Please send comments, suggestions, corrections, and feedback to Erica Gaddis: Erica.Gaddis@uvm.edu.
Gund Institute for Ecological Economics, 610 Main Street, Burlington, VT 05405
November 9, 2005
St. Albans Landscape Modeling Working Group
STORMWATER RUNOFF
24
Parameter/Assumption
TP concentration (mg/l)
25
Soil test phosphorus in
city/residential soils.
26
P runoff in storms and spring
runoff.
*27
Determine which urban/
residential/commercial areas
are already serviced by
detention ponds. Estimate
detention capacity.
Value
Source
0.27 - 0.33
National Stormwater
Quality Database;
National Urban Runoff
Program
Interpolated from
sampling around city OR
Average input for all
residential/commercial/
public landuse.
Determined empirically
based on monitoring
effort.
St. Albans town? ANR
Stormwater section?
Comments
WASTEWATER DISCHARGE
28
29
30
31
32
33
Parameter/Assumption
Permit Effluent TP
concentration (mg/l)
Permit Flow (mgd)
What is the current average
flow?
How much rain is required to
cause an overflow of the
wastewater system?
Estimate how much P lost in
wastewater overflow.
Where does the wastewater
treatment plant discharge?
Value
0.5
2.39
Source
Comments
Lake Champlain TMDL
Lake Champlain TMDL
St. Albans Public Works?
St. Albans Public Works?
St. Albans Public Works?
St. Albans Public Works?
Please send comments, suggestions, corrections, and feedback to Erica Gaddis: Erica.Gaddis@uvm.edu.
Gund Institute for Ecological Economics, 610 Main Street, Burlington, VT 05405