phase 5 update

Phase 5 Update

Gary Shenk

7/13/05

Modeling Subcommittee

Outline

• Sediment Phase5.0 wrap-up

• Nutrient simulation setup

• Nutrient input data descriptions

Sediment Pathway in Phase 5

BMP Factor

Land Acre Factor

Delivery Factor

Edge of Field

Edge of Stream

1. Sediment processes are simulated on the land surface resulting in an Edge-Of-Field sediment load.

2. A time series of Best Management Practice (BMP) factors is applied based on available data.

3. A time series of land use acreage factors is applied.

4. A delivery factor based on local geometry is applied (see below), resulting in the Edge-Of-Stream load.

5. Processes of deposition and scour are simulated in the stream, resulting in concentrations that can be compared to observations.

In Stream Concentrations

1. Define Targets

• Pasture => Pasture• Poor Pasture => 9.5 * Pasture• Hay => 1/3 Crop (P4 NRI)• High till with manure => 1.25 * Crop• High till no manure => 1.25 * Crop• Low till with manure => 0.75 * Crop

Agriculture

9%

0.05%

7%

4%

1%

4%

Land use % of model Target relative to NRI estimate

NRI provided direct estimates for Pasture. Poor Pasture is pasture that is heavily trampled near streams. It is a small land use that exports at a high rate. NRI provided estimates for Hay for the phase 2 model. The estimates were generally 1/3 of crop for that data set, so the proportion was kept. Low till is generally 40% lower than High Till, so that ratio was applied with an average value of the NRI estimate.

2. Define Desired Behavior

Runoff, Washoff, and Sed Storage

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

3650 3670 3690 3710 3730 3750Days

wa

ter

(in

/d);

Se

d (

t/d

); S

ed

Sto

r (t

on

s)

surodetswssd

3. Reduce Parameter Set

KSER

Detached Sediment

Soil Matrix(unlimited)

Wash off

Rai

nfal

lD

etac

hmen

t

Att

achm

ent

KRER AFFIXNVSI

Gen

erat

ion

4 parameters, 1 target

Correlation of sediment concentrations for each of 8 scenarios

4. Find Best Values for Parameter Relations and Calibrate

Greater effect of plowingMore hysteresis

Legend

P5 Calibration Stations

# of Observations

0 - 100

101 - 300

301 - 500

501 - 1000

1001 - 5000

River Calibration• Calibrated at ~130 sites with flow

and TSS data.• Used system of rules for hand

calibration.• No method of automated

calibration developed so far.

Potomac Fall Line – Raw Data

‘Windowed’ comparison

• If simulated or observed value is below 10 mg/l set it to 10 mg/l.

• Check simulation for 24 hours before and after observation and set simulated value to point closest to observation.

Of the highest observed and simulated peaks at all calibration stations, almost as many peaks occurred one day apart, but few occurred on two days apart

One day apart – 83% of the same day figure

Two days apart – 19% of the same day figure

Potomac Fall Line

Status - Sediment

• Phase 5.0 complete

• Refinements expected in land-to-river delivery ratio

• Automated river calibration will be investigated

• Phase 5.x– To come out periodically over the next 18

months, with advances in calibration methods and input data

Nutrient Calibration

BMP factor

Land Acre FactorDelivery Factor

Edge of Field

Edge of Stream

Nutrient CalibrationEdge of Field

• Based on Targets acquired from 3 sources:– Literature Survey– Sparrow analysis of land use– Mass Balance

Nutrient CalibrationEdge of Field

• Calibration Methodology– Calibrate for small trend in nutrient storage

and to hit the targets – Based on experience with phase 4– Hundreds of parameters controlling export;

fewer are sensitive

Trees

Roots Leaves

ParticulateRefractoryOrganic N

ParticulateLabile

Organic N

SolutionAmmonia

Nitrate

SolutionLabile

Organic N

AdsorbedAmmonia

SolutionRefractoryOrganic N

Nitrogen Cycle in Watershed Model ForestA

tmos

pher

ic

Dep

osit

ion

Den

itri

fica

tio

n

Export

Export Export ExportExport Export Export

After HSPF documentation

Land Uses Simulated

• Forest• Harvested Forest

• Low Intensity Pervious Urban• High Intensity Pervious Urban• Low Intensity Impervious Urban• High Intensity Impervious Urban• Bare-construction

• Extractive• Natural Grass

• High Till with manure• Nut Man High Till with manure• Low Till with Manure• Nut Man Low Till with manure• High Till without manure• Hay with nutrients• Nut Man Hay with nutrients• Hay without nutrients• Alfalfa• Nut Man Alfalfa• Pasture• Nut Man Pasture• Trampled• Animal Feeding Operations• Nursery

Differences between p4 and p5

• Phase 4 used a combination of coefficient modeling (PQUAL) and mass balance modeling (AGCHEM). Phase 5 will be all mass balance modeling

• Phase 4 reset the mass balance at the end of each year to stabilize the simulation. In phase 5, we will attempt to stabilize without resetting

• Parameters governing nutrient uptake will change during the simulation to reflect crop makeup.


BMP factor

Land Acre FactorDelivery Factor

Edge of Field

Edge of Stream


BMP factor

Land Acre Factor Data Sets Under Development


Delivery Factor

Phosphorus similar to sediment?

Assume nitrogen targets are already EOS?

Take land-to-river and small stream delivery factors from Sparrow?


Initial river calibration will be similar to the sediment calibration methodology

Calibration by hand

Determine sensitive parameters

Determine calibration rules

Nutrient Status

• Simulation “on the graph paper”

• Still need some inputs, but we are running sensitivity while we are waiting

Nutrient Inputs

• Dry Atmospheric Deposition

• Crop Uptake

• Manure and Fertilizer Applications

• Septic

Crop Need and Nutrient Uptake

• Model requires monthly max Crop Uptake

Uptake = (Max Yield) * (Nutrient Content)

• Max Yield – Ag Census, STATSGO

• Nutrient Content - from USDA plant nutrient content database.

• Monthly uptake fractions varied by USDA plant hardiness zones

Crop Need on Composite Crop*Phase 4 Crop Need Phase 5 Crop Need

•Crop need calculated for a corn, soy, small grain composite crop after legume credit. Needs range between approximately 50 and 150 lbs / acre for both phases.

Low

High

Nutrient Loading Rules

• Manure stays in a county unless transport data are supplied.

• All fertilizer sold in the model domain is divided between land uses and regions such that all land uses receive a constant multiplier of crop demand, except:

• Nutrient Managed lands receive less nutrients. N or P based.

0.0

10.0

20.0

30.0

40.0

50.0

60.0

70.0

80.0

90.0

Nit

rog

en

lb

s/a

cre

Fertilizer N

Manure N

Legume

All Nitrogen Sources 1982-2002

All Phosphorus Sources 1982-2002

0.0

5.0

10.0

15.0

20.0

25.0

19

82

19

87

19

92

19

94

19

96

19

97

19

98

19

99

20

00

20

01

20

02

20

03

Ph

os

ph

oru

s lb

s/a

cre

Fertilizer P

Manure P

Septic Systems

• Calculated from U.S. Census. 1970-1990• Load = fraction on septic * people * load per

person• Fraction on septic extrapolated from trends

(1970, 1980, and 1990). • People from census estimates and projections• Load per person is a constant.• distributed to land-river segments based on low

density residential acreage.

Septic Loading RateSystems per acre Low-Density Total Number of Systems

•Septic Accounts for approximately 4% of total N produced in the watershed. Darker color indicates higher density.

Low

High

New Code

• HSPF13 - Previously available only for Lahey fortran on PC

• Programmed unimplemented intrinsic functions

• Provided ‘work-arounds’ for non-gcc features

• Made linux compilation scripts.

• Submitting to Aquaterra for clean-up.

Schedule

• July – Sensitivity tests and setup

• August – Edge-of-Stream automated calibration

• September – Hand calibration of Rivers

• October – Get phase 5.0 nutrient loads to WQM

phase 5 update

Documents

small land

simulated value

land surface

data set

simulated peaks

high till

calibration methods

hand calibration