FLOOD02983

• County: Arapahoe
• Community: Littleton
• Stream Name: Lee Gulch, Little Creek
• Basin: South Platte
• Title: Major Drainageway Planning
• Date: 9/1/1978
• Prepared For: Littleton
• Prepared By: UDFCD
• Contract/PO #: &&
• Floodplain - Doc Type: Floodplain Report/Masterplan

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Mr. Ben Urbonas, P.E.
Page Three
December 14, 1977

Mr. Ben Urbonas, P.E.
Page Four
December 14, 1977

In regard to the side channel spillway on the Highline
Canal, this recommendation is legally sound and should be
reviewed with the canal owner to obtain its permission, if any
alterations of the canal would be necessary. Also, the feasibi-
lity of obtaining funds from the canal owner for the construction
of this improvement should be investigated since it would seem
that if the policy of separating irrigation and drainage flows is
followed, this improvement is necessitated solely because of the
canal and its condition. But if the drainage flows entering the
canal are a result of others dumping their drainage flows into
the canal then and in that event the canal owner should not be
required to bear such an expense as the suggested improvement.

Finally, when the final design for this project is com-
pleted, the engineer should address himself to the sequence of
implementation of the recommended alternatives so that any
increased damage upstream, downstream, or adjacent to the improve-
ments as a result of the sequence of implementation of the selected
alternatives can be avoided.

II. Lee Gulch.

This portion of the opinion will proceed from the
"uphill" portion of Lee Gulch and comments will be made on all
three reaches of the gulch and the alternates discussed and selected
in the engineer's report.

In regard to the flume with a clear span crossing, it appears
that this recommendation of leaving it up to the owner of the canal
is certainly correct if it has been determined that the flume as it
is now will not be further damaged by any improvements that are
recommended upstream. If there is further damage as a result of
our improvements, there is an obligation to prevent this portion
of the damage. Here, the overriding consideration is that the flu~e
was built by the owner with its supports in the flood plain and,
therefore, it has created the problem.

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1. Reach 3.

It appears from the report that no structural
alternates were evaluated or selected in this reach and that the
sole recommendation in this reach is the zoning of the 100-year
flood plain as such. This alternative is satisfactory for the con-
ditions at present because of the lack of any structures in the
Reach, but it would seem advisable to also, at this time, address
the problems and potential problems which may exist in the Reach
with full development of the Reach. It is not clear from the report
that this has been done, although there is some indication in the
report that there exists a preliminary plan for a subdivision in
the area of the Reach. This expansion of the engineer's report
would be necessary for Arapahoe County to intelligently evaluate
the development of the Reach and the determination of what flood
control measures will be imposed on the developers of the area.

3. Reach 1.

The recommendation made in Reach 1 are legally
satisfactory as long as they meet the criteria set forth in my genecal
comments.

In conclusion, the engineer has recommended zoning the 100-
year flood plain which, of course, should be done, but further, all
commercial industrial, and residential occupants of the flood
plain should be notified of their situation.

2. Reach 2.

The channelization of the south branch east of
Broadway and south of the industrial building is legally satisfactory
as long as the criteria in my general comments are met. The damage
of the four street crossings in this Reach is mentioned, but no
opinion is stated as to the effect, if any, the recommended channeli-
zation has on at least three of these streets. It would be of
assistance in reviewing the final design to have this type of
information along with other alternates that were looked at to solve
or reduce this problem. The suggestion of the cost of channeliza-
tion in the area of the industrial building is a good one, but it is
not clear what facts justify such a suggestion. If the flooding
in the parking lot and industrial building is a result of the
owners' acts, then this idea would have some legal basis.

III.

Little Creek.

This portion of the opinion will also proceed from the
"uphill" portion of Little Creek and comments will be made on all
six reaches of the creek and the alternates discussed and selectee
in the engineer's report.
1. Reach 6.

The alternates discussed and selected in this
Reach are legally satisfactory and the only thing unclear to me is

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