a short primer on the prism2 dss

A Short Primer on the PRISM2 DSS

Paul Conrads, USGS

Drought and Salinity Intrusion Workshop December 14, 2011

Memory Lane

2002

Quiet Desperation Bull Creek Intake

Fast Forward

FERC

Re-licensing

PRISM: Controlled Releases Effect on Salinity Intrusion

What causes the large salinity intrusions along the coast?

What is the minimum flow to control salinity intrusion?

Is there enough water in NC to control salinity intrusions?

Data Mining

The physics is manifested in the data

Learn/quantify important cause-effect relations

Data driven models

are “virtual processes”

evaluate alternatives

Description of the Salinity Models

Cascading models

1st Simulates daily SC response

2nd simulates hourly SC response

Decomposed

Water-level signal

Input Data for Models

Riverine Flows

Pee Dee*

Little Pee Dee

Lynches

Black

Waccamaw

*User controlled input

Tidal Forcing

Mean Water level

Tidal Range

Little River Inlet

Note: Specific

conductance is not

used as an input

Freshwater

Saltwater

SC Model – Hagley Landing

Black – measured Gray – simulated

Model Performance Pawleys Island

Decision Support Systems

Models embedded in an Excel application

Integrates:

Historical database

Models and model controls

Streaming graphics

Optimization routines

Simulation outputs

Excel levels the technical playing field

DSS Architecture

Graphical User Interface

Application Controls Simulation controls –

period and time step

Flow control –

percent historical or

constant

Input data –

Wind speed

and direction

Water levels

Flows

Graphical Display

Input data - wind,

water level, and flow

Specific Conductance

– daily predictions

Specific Conductance

– hourly predictions

Actual data –

black

Model

prediction –

red

User

specified

condition –

green

Difference

b/w user and

actual - gray

Looking Inside the Black Box

3D response surfaces Surface created by

ANN model

“Unseen” variables set to constant value

Manifestation of historical behavior of system

Insight to the process dynamics or physics

What Conditions Cause Large Intrusions?

High

water

Low

water

3-D Response surface – Q, XWL, and SC

Low Coastal Water Level High Coastal Water Level

Convergence of Conditions

PRISM2: Threaten Intakes along SE Coast Due to Climate Change

• Sea-level rise

• Changing

streamflow

patterns

• Inputs from

GCMs

PRISM > PRISM2

User control of uncontrolled and controlled rivers

User control to bias sea levels

User specified hydrographs for rivers

PRISM2: User Controls

Riverine Flows

Pee Dee*

Little Pee Dee*

Lynches*

Black*

Waccamaw*

Tidal Forcing

Mean Water

level*

Tidal Range

Little River Inlet

* User controlled inputs

Freshwater

Saltwater

Conceptual Model

Precipitation

Temperature

Global & regional

circulation models

Gridded rainfall

input to watershed

model Watershed model

<Sea-level rise

Salinity intrusion

model

Data Stream

Precipitation

Temperature

Geo Data Portal

GCM downscale

data

HSPF

Watershed model

<Sea-level rise

PRISM2

• Upload shape file of study area

• Climate data for each sub-

watersheds

24

• Configure retrieval statistics/format

• Pull data for any number of

models and scenarios

• User-defined climate projection

period

25

PRISM2: Splash Page

Run Page

Input Set Points Page

User Defined Hydrographs

Output

• 132 output columns

• All input values

• All input setting

• Measured values at each

gage

• Model Output

• Measured

• User specified

• Delta

• Measured + delta

• Daily & hourly values

Results – Sea-level Rise Grand Strand – Pawleys Island Gage

Simulated a 0.5, 1.5, 1.5, 2.0, 2.5 and 3.0 ft SLR

14 year simulation

Comment on extrapolation

Large range in historical data

annual coastal water levels

Lower ranges of SLR (<2.0 ft) within range of historical data

Output Example 25% Reduced Flows

Flows and Delta SC

Sea-level rise projections Springmaid Pier

Local Trend

Modified NRC-III

Modified NRC-II

Modified NRC-I

Analysis based on USACE methodology

Multiple Model Runs Results - SLR Grand Strand – Pawleys Island Gage

14 year simulation

0.5 ft incremental SLR up to 3 ft

Results – SLR & Reduced fow Grand Strand – Pawleys Island Gage

Reduced flows by 5% up to %25

Figure 1. Study area including the Pee Dee and Waccamaw River Basins and Atlantic Intracoastal Waterway in South Carolina.

Pee Dee Flows Waccamaw Flows

Tidal range 3 ft

Tidal range 4 ft

Freshwater slug With sea-level rise, appears

that it will push more

freshwater to the north.

Water level rises in the

“slug” and forces more

water to the north and

pushes out the salt.

Pee Dee,

Wacammaw and

AIW

System Behavior

South End Response

North End Response

Paul Conrads

USGS South Carolina Science Center

pconrads@usgs.gov