Water Quality Model for El Cajon Reservoir

Oliver Obregon and Clark BarlowBrigham Young University,

In collaboration with

ITESO University

HEC-HMS Long-term Simulation of Cuenca Cajon

Oliver Obregon, Thomas Lloyd, Clark Barlow

Brigham Young University

Project Location

Issues

Dams are planned and under construction along the Santiago River in the Cajon watershed

Mexican engineers would like to be able to predict how quickly new dams will be filled with water

Model Background

• What is HEC-HMS?Capable of long-term, distributed (gridded)

simulations

Methods Used within HEC-HMS– SMA (Soil Moisture Accounting)– MOD Clark

Method Information

• True long-term simulation

• Uses parameters such as canopy storage, groundwater storage, infiltration rates, evapotransporation rates, etc.

SMA

• Requires fewer parameters

• Better suited for single storm events (short-term simulations)

• SCS based method

MOD Clark

HEC-HMS SMA Method

• Information Gathered

DEMs, Dam locations, Soil and Land Use Data (not used)

• Information Not Gathered

Everything else

SMA Project Approach

1. Using real and fabricated data, built a running, working model

2. Created a HEC-HMS SMA tutorial

3. Created a parameter optimization tutorial

HEC-HMS MOD Clark Method

• Information Gathered– DEMs,

Dam locations, Soil and Land Use, Precipitation (Tepic)

• Assumptions– 25 x 25 grid– Precipitation data

was representative– Two month

duration (wettest months)

MOD Clark Project Approach

1. Created CN table for land use and soil data

2. Used average daily precipitation values (6-hour and daily increments)

3. Used actual daily precipitation data from July-August 2006

HEC-HMS MOD Clark Results6

ho

ur

I d

ay

HEC-HMS MOD Clark ResultsA

ctu

al P

reci

pit

atio

n,

Lin

ear

dis

trib

uti

on

HEC-HMS MOD Clark ResultsA

ctu

al P

reci

pit

atio

n,

Mo

dif

ied

Typ

e II

dis

trib

uti

on