EP 1110-2-9
31 Jul 94
(a) Obtain precipitation records.
a. Select computer program (HEC-1F, SSARR, etc.)
to be used. Factors to be considered are: size and com-
(b) Calibrate model.
plexity of basin (reservoir projects, diversions, etc.); type
of runoff regime (rain, snow, flash flood potential); and
(c) Apply precipitation, compute hydrograph.
applications required (flood operations, low-flow
forecasting).
(d) Display, verify reasonableness.
(1) Review information and models; consult as
c. Compute volume of water stored for each flood,
necessary with users and experts.
given the planned flood regulation plan.
(2) Obtain models, run tests.
(1) Determine computational technique, e.g., spread-
sheet, existing model such as the Hydrologic Engineering
(3) Evaluate resources needed for real-time applica-
Center (HEC-5), etc.
tion (computers, people, funds).
(2) Prepare spreadsheet/model, check with test data.
(4) Select model.
(3) Establish regulation rules, assumptions of forecast
b. Review historic and real-time data availability and
knowledge.
obtain hydrometeorological data pertinent to forecasting
and project operation. Process data for input to forecast
(4) Perform routings using newly derived inflow data.
model.
(5) Display results, review for reasonableness.
(1) Set up forecast database (likely (HEC-Data Stor-
age System)).
d.
Construct seasonal flood control rule curve.
(2) Consider data types needed (precipitation, tem-
(1) Plot storage requirement as a function of date.
perature, streamflow, etc.).
(2) Plot tentative envelope line representing rule
(3) Examine period of record and select flood events
curve. Incorporate limitations for rate of draft, etc.
that should be used in calibrations.
(3) Identify outlier points, estimate probability of
(4) Obtain data and download to database.
event. Decide whether to envelop or not.
(5) Perform data screening/data display to verify
(4) Identify impacts on other project functions and
data.
compare with rule curves used in project authorization.
c. Choose likely hydromet station candidates for
(5) Decide upon final rule curve.
real-time application.
E-5. Develop Forecasting Model
(1) Review performance of existing real-time
telemetry.
Assess whether the project under consideration warrants a
forecast model as a part of the reservoir regulation activi-
(2) Examine feasibility of providing future
ties, and whether staffing is available to maintain and
operate the model. If that assessment is affirmative, then
a model is needed for future operational application. It is
(3) Determine relative merit of stations as indices to
likely that an existing study model can be used as a basis
forecasting runoff.
for development of the forecasting model. Assess
whether forecasting is also to be done for conservation
(a) Compute correlations of precipitation versus
operation purposes, as well as flood control. If so, a
runoff.
continuous model capable of forecasting low-flow condi-
tions might be the appropriate choice.
E-2
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