I. Authorizing Resolution Passed by the Wastewater Utility’s Governing Board for the Sponsored

Project Application

This project is included in the City of Ames F2013-2018 Capital Improvements Plan (CIP) that was

authorized by the Ames City Council in Spring 2013. Enclosed with this application is the page from the

CIP that specifically address this project.

II. Letters of Support from Project Partners

The Iowa Department of Natural Resources has served as a partner on this project. Enclosed with this

application is a letter of support from Nate Hoogeveen, the River Program Coordinator.

III. Letter from the Wastewater Utility’s Bond Counsel Indicating Concurrence with the Sponsored

Project Concept

Dorsey & Whitney, LLP serves as bond counsel to the City of Ames. Enclosed with this application is a

letter of concurrence with the Sponsored Project concept.

IV. Assessment of the Impacted Waterbody and its Watershed with Data that Supports the

Identification of the Water Quality Problems to be Addressed.

Iowa DNR Provided a copy of a Flathead Catfish Study which shows that for the South Skunk River, the

13th

Street Dam in Ames, IA serves as an obstacle to passage. No Flathead Catfish have been sampled

upstream of the 13th

Street Dam since 1970. Sampling for other species of fish has shown similar results,

including only one Channel Catfish since 1970. The South Skunk River page from the Flathead Catfish

Study has been enclosed with this application.

V. Discussion of Project Goals and Objectives

In-stream Habitat Enhancements

The proposed modifications to the 13th

Street Dam will allow fish passage upstream to the Hannum’s

Mill Dam. The Hannum’s Mill Dam is the only dam upstream preventing fish passage to the entire South

Skunk River. The Oakland Mills Dam is 188 river miles below the 13th

Street Dam. Access to headwaters

on the Des Moines Lobe geological landform will be important for the fishery. The segments of river

immediately upstream of Ames contain cobble and rock substrates that are not available in many other

portions of the South Skunk River.

The existence of the dam likely limits the populations for certain species that would typically be in

place, such as deepwater overwintering ictalurids like channel catfish and flathead catfish. The period of

sampling record upstream of the 13th

Street Dam saw only a single channel catfish sample in 1970 with

30 subsequent years of records, and no flatheads during the same period. These would be the primary

species to benefit. Additional species that are present downstream, but not upstream of the 13th

St dam

include Bullhead Minnow, Channel Shiner, Emerald Shiner, Freshwater Drum, Longnose Gar, Shortnose

Gar, Shoal Chub, Slenderhead Darter, and Smallmouth Buffalo. Additionally, the Creek Heelsplitter and

Paper Pondshell species of mussels would also benefit from biological connectivity resulting from this

project.

Installation of Natural Channel Design Techniques

The proposed modifications to the 13th

Street Dam will use natural channel design techniques

including the strategic placement of weir boulders, base stone, and gradation stone to direct the flow as

well as pool water and protect the river bank. These natural channel design techniques will help protect

the river bottom and river banks during periods of high flow by reducing the concentration of kinetic

energy immediately downstream of the dam. The highest velocities will also be directed away from the

sides of the river and will be slowed downstream of the dam by installation of a j-hook configuration of

natural stone.

VI. Evaluation of Alternatives Considering the Unique Demographic, Topographic, Hydrologic, and

Institutional Characteristics of the Planning Area

Project Alternatives

Many alternatives were considered since the inception of this project. Public meetings were held to

receive stakeholder input and develop a design that accommodated those needs. The one constraint

from the beginning was that the 13th

Street dam cannot be removed altogether. The reason the dam

was originally built was to provide groundwater recharge to the aquifer serving the City of Ames

drinking water wells. During periods of drought, the dam has proven invaluable at mitigating the effects

on the groundwater supply to the City of Ames.

With removal of the 13th

Street Dam eliminated as an alternative, the stakeholder needs were taken

into account. The arched rock rapids design with weir boulders, base stone, and gradation stone was

chosen because it used natural channel design techniques and it provide the greatest in-stream habitat

enhancements to fish and mussels in the South Skunk River. The current design also will provide

recreational opportunities for canoeing and naturalist groups, as well as eliminate the dangerous

hydraulic circulation that has caused so many deaths throughout Iowa in recent years.

In approximately the past two years, the project has become more expensive due to required

hydrological modeling and increased materials costs. While determining whether to continue with the

project, the City of Ames met with Nathan Young at the Iowa Institute for Hydraulic Research in Summer

of 2012, to discuss alternative designs. It was determined at that time that, excluding dam removal,

there are no lower-cost design alternatives that could be pursued that would provide the in-stream

habitat enhancements, natural channel design techniques, as well as meet the other needs of the

stakeholders.

VII. Description of Practices to be Implemented with the Expected Water Quality Outcomes

The Iowa Department of Natural Resources – River Programs has worked closely with the City of Ames

to develop a design based on the principles outlined in various publications by Luther Aadland on the

topic of Natural Channel Design. Enclosed with this application is documentation on the design for the

project.

VIII. Discussion of project locations, land ownership, and any plans for acquiring properties or

easements

The project is located in North River Valley Park upstream of 13th

Street. The property is owned by the

City of Ames and, due to its design footprint, no acquisition of property will be needed for this project.

Figure 1 – Aerial of Low-Head Dam in City of Ames at North River Valley Park.

Figure 2 - View of Low-Head Dam in City of Ames at North River Valley Park, looking north.

IX. Identification of Any Other Organizations or Resources to be Involved in the Project and their

Expected Contributions

Other organizations that have been involved with this project include the Skunk River Paddlers, the

Hawkeye Fly Fishing Association, and individual citizens. Verbal commitments of funding have been

made to this project, from some individuals and groups, but no money has actually been donated at this

time.

X. Proposed Project Schedule with Major Milestones

Project Event/Milestone Date

Application for Sponsored Projects Funding Submitted July 19, 2013

Public Hearing November 14, 2013

Public Comments Closed November 21, 2013

Commission Meeting & Approval December 17, 2013

Complete Hydraulic Modeling January 2014

Begin Construction June 2014

Complete Construction September 2014

XI. Proposed Evaluation Procedures and Measures

Biological and Physical Monitoring Data

Several decades of fish population and community samples exist for sites upstream and downstream

along the South Skunk River. Iowa DNR has indicated in past grant proposals that Channel Catfish and

Flathead Catfish populations could be targeted for increased sampling in the future after modifications

to this dam have been completed. This could also include tagged releases downstream of the 13th

Street

Dam. Monitoring for tagged releases downstream would provide verification that the proposed

modifications were successful.

30

LOW-HEAD DAM MODIFICATIONS PROJECT STATUS: Scope Change Delayed

Cost Change City of Ames, Iowa Capital Improvements Plan

DESCRIPTION/JUSTIFICATION

This project will modify the low-head dam in North River Valley Park. The primary purpose is to reduce the risk of drowning due to a hydraulic recirculation downstream of the dam. Additional benefits of the improvements include increasing the recreational opportunities for paddlers and kayakers, and creating an opportunity for fish to migrate upstream past the dam.

COMMENTS

The low-head dam in River Valley Park serves an essential function during periods of sustained drought by pooling water in the primary recharge zone for the Water Plant�s Downtown Well Field. This type of dam has the potential to create a dangerous hydraulic recirculation downstream of the dam. The recirculation can trap a person below the surface and can lead to drowning in just a few feet of water. A conceptual proposal has been developed jointly between the City of Ames and the Iowa Department of Natural Resources that will achieve the primary goal of improved safety, while also providing additional recreational opportunities for paddlers and kayakers. The design would also facilitate the movement of fish upstream past the dam, helping to increase the upstream fish population diversity.

The project was originally shown in the FY 10/11 CIP at an estimated cost of $150,000. The City received a grant award of $75,000 from the state�s Low-Head Dam Public Hazard Grant program. Over the past two years, staff has been unsuccessful in receiving permit clearance for the original design concept. Work with the Iowa Department of Natural Resources and the Iowa Institute for Hydraulic Research has resulted in a design that should be able to receive permits from the necessary agencies but at a higher cost estimate of $225,000. Staff is pursuing additional grant opportunities to help absorb the cost increase, although an additional $25,000 has been added to the Water Fund�s contribution compared to the FY 12/13 CIP carryover. Should the City be unsuccessful in securing the additional grant funds, Council would need to decide whether to pursue the project by allocating additional local funds. Construction is now anticipated in fall 2013, but will be highly dependent on river levels.

LOCATION

North River Valley Park, E 13th Street � Map 6, location O-9

FISCAL YEAR PRIORITY 3TOTAL 2013/14 2014/15 2015/16 2016/17 2017/18

COST:

Construction 225,000 225,000

TOTAL 225,000 225,000

FINANCING:

Water Utility Fund 75,000 75,000Low-Head Dam Public Hazard Grant 75,000 75,000Other Grant Funding 50,000 50,000In-Kind Donations 25,000 25,000

TOTAL 225,000 225,000

PROGRAM - ACTIVITY: DEPARTMENT: ACCOUNT NO.

Utilities � Water Water & Pollution Control 510-3938-489

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ST232

882.2

WEIR E

ST205

882.2’

ST175

882.3

WEIR D

ST136

882.4

WEIR C

ST85’

882.5

WEIR B

ST -3’

882.7

WEIR A

ST163

882.3’

ST125

882.4

ST72

882.5’

ST -3

882.7’

~24 randomly

spaced

boulders (3’ to

6’ dia)ST292

884’, J-HOOK;

exact station

may be

adjusted after

weirs A-E are

constructed;

structure

mostly

submerged

ST270; 877’;

J-HOOK tip

(3-5’ boulders,

2 rows, 1 as

footer)

Materials notes

1) Weir boulders/randomly spaced boulders can range from

3’-6’ diameter (70% ≥ 3’ diameter, 20% ≥4’, 5% ≥5’)

2) Flat slab boulders on near bank may need to be limestone

quarry run. Speci#c weight of 1.5 or greater is preferred.

Variations in thickness (1’) can be accomodated by varying

size of materials below.

3) Filter (.1’ to .5’ mix of gravels and cobble; enough gravels

may be excavated from streambed for footers, but .2 to .6’

stone of ~10 percent volume or tonnage of base stone will

be needed.)

$at slab boulders

along bank as

walking surface,

~1’ x ~4’ x ~4’,

grouted, double

as anchor

boulders for weirs

(i.e., use elevations

listed for ends)

Stair steps,

dimensions to

be designed

by City

880.5’x

880.5’x

881x

881x879.7’x

879.7’’x

880.2x

xST54880.2

878.9’x

879.4’

x

x

x878.9’

879.4’

878.6’

878.1’

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xx

878.1’878.6’

x

x

x

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879

x

xxx881.5 881.3

880.2879

Placement notes

1) Trough .5’ lower than neighboring stones for both base

material and weirs. Weir A does not have an abrupt trough

due to the already constricted cross section.

2) Nested weirs should have a parabolic shape both in the

plan view and in elevation. This is di&cult to display in a cross

section because the arches are 3-dimensional. Looking at the

weir A cross section should help clarify ... the weir should

drop in elevation most rapidly from the banks and $atten out

near the edges of the trough. Spot elevations (yellow x)

should also help clarify.

2) Footer stones are shown at the edges, and for the j-hook.

At the edges, these will be necessary to brace weir stones at

the cabled concrete. Place downstream & at lower elev.

3) Weir stones must be carefully placed to interlock, and

brace from upstream to downstream for maximum stability.

Weir A stones will brace on dam. and some base/#ll will be

hand-placed.

x 881

x 881x 880

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Plan view, 13th Street Dam Hazard

Mitigation recommendations

ed

xx

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s to

ed

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ST 90 Cross

Section (dashed)

105

Skunk River (Figure 7) - There are multiple recent and historic collections of various size classes

of flathead catfish from the Skunk River and South Skunk River between its confluence with the

Mississippi River and the 13th

Street Dam (< 4 ft. tall) in Ames. The Oakland Mills Dam (9 ft.

tall) near Mt. Pleasant is the only dam in this section of river that is a barrier to upstream fish

movement. Although this dam is listed as 9 ft. tall, the effective height of the structure is much

lower and it is not believed to be a barrier to upstream fish passage during high flows (Vance

Polton, Iowa DNR, personal communication). There are also several recent and historic

collections of multiple size classes of flathead catfish from the North Skunk River between its

confluence with the Skunk River and the Wagaman Mill Dam (10 ft.). Several recent collections

have also documented multiple sizes classes of flathead catfish in Cedar Creek and Big Creek.

The presence of individual flathead catfish has been documented by recent samples in Middle

Creek (tributary of North Skunk River), and Indian Creek (tributary of South Skunk River. There

is evidence of flathead catfish populations in the South Skunk River downstream of Ames, the

North Skunk River downstream of the Wagaman Mill Dam, the entire Skunk River, Big Creek,

and Cedar Creek.

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Stream order