Initial Monitoring Results

and Performance

Presentation Date:

February 11, 2015

• County of Cochise, AZ

• The Nature Conservancy

• JE Fuller/Hydrology &

Geomorphology, Inc.

• GeoSystems Analysis, Inc.

• Project Background

• Construction Summary

• Monitoring Equipment Installation

• Monitoring Period

Data presented today represents the initial results of monitoring the

system for a brief period of time. As this is a pilot project, long-

term results and conclusions will be used to inform future projects,

and guide improved analyses and design practices.

• Palominas,

Cochise County, Arizona

• Approximately 15 miles

South-Southeast of Sierra

Vista

• Rural setting

• Property often referred to

as the Mansker Tract

In-Channel

Basins Palominas

School

Detention

Basin

Stockpile

Box Culvert

Detention

Basin

Primary

Outlet

Overflow

Weir

6-Inch Weep Holes (3)

@ Stage=0.0’

Grate Inlet

@ Stage=3.0’

3-3.0’ Diameter

Corrugated Metal Pipes

265’ Crest Length

@ Stage=6.5’-7.0’

In-Channel

Basins (13) Weir Walls

(16)

Drywells

(6) Gravel Infiltration

Trenches (3)

Basins and Weir Walls

Single-Cell Shown

Dual-Cell Also Installed

• Monitoring Program Objectives

• Determine Volume of Stormwater Captured

• Determine Volume of Water Infiltrated

• Estimate Recharge

• Equipment Installed

• Precipitation Gages

• Stilling Wells in basins, drywells and infiltration trenches

• Groundwater monitoring to determine GW elevations

• Soil moisture monitoring to determine soil-water dynamics

• Monitoring Period

• July 2014 to present

• Data Presented Today for July 2014 through mid-November, 2014

0.0

1.5

3.0

4.5

6.0

7.5

9.0

10.5

12.0

13.5

15.0

16.5

18.0

0.0

0.3

0.5

0.8

1.0

1.3

1.5

1.8

2.0

2.3

2.5

2.8

3.0

Ave

rag

e C

um

ula

tive

Pre

cip

ita

tio

n (in

)

Av

era

ge

Da

ily P

rec

ipit

ati

on

(in

)

Date

Average Daily Precipitation Average Cumulative Precipitation

Odile

• Average summer

precipitation (9.98

inch) until Odile

• Odile and

subsequent frontal

storms = 7.03 inch

• Wet year!

Monitoring

LocationYear

Average

Precipitation

(in)

Seasonal

Rainfall

Classification

Palominas

Watershed2014 17.01 Wet

1955 - 2011 9.99 Avg

1964 (max) 19.08 Wet

1962 (min) 2.81 Dry

Stdev 3.53 --

9.99 Avg

13.52 Wet

6.46 Dry

Historical

Seasonal Rainfall

Classification

0

0.5

1

1.5

2

2.5

3

3.5

Wa

ter

He

igh

t (f

t)

Date

Detention Basin SW-1 SW-2

SW-3 Weir 1 Crest Weir 2 Crest

Weir 3 Crest Detention Basin Sump Crest

Odile

0

0.5

1

1.5

2

2.5

3

3.5

Wa

ter

He

igh

t (f

t)

Date

SW-4 SW-5 SW-6 Weir 4 Crest Weir 5 Crest Weir 6 Crest

Odile

0

0.5

1

1.5

2

2.5

3

Wa

ter

He

igh

t (f

t)

Date

SW-7 SW-8 SW-9 Weir 7 Crest Weir 8 Crest Weir 9 Crest

Odile

0

0.5

1

1.5

2

2.5

3

Wa

ter

He

igh

t (f

t)

Date

SW-10 SW-11 SW-12 SW-13

Weir 10 Crest Weir 11 Crest Weir 12 Crest Weir 13 Crest

Odile

15

20

25

30

35

40

45

50

De

pth

to

Gro

un

dw

ate

r (f

t)

Date

Baseline Well East Well Central Well West Well

Odile

Corrected

Weephole

Outflow (AF)

V-notch

Overflow

(AF)

Weir Wall

Overflow

(AF)

Total

Outflow

(AF)

Total ET +

Infiltration

(AF)

Detention Basin 36.48 N/A NA 36.48 NA

Basin 1 13.78 1.80 5.43 21.01 15.48

Basin 2 9.41 1.13 4.40 14.94 6.07

Basin 3 9.45 1.14 2.34 12.93 2.01

Basin 4 3.21 0.43 0.39 4.03 8.90

Basin 5 2.56 0.16 0.00 2.72 1.31

Basin 6 2.41 0.24 0.00 2.65 0.07

Basin 7 0.00 0.67 0.47 1.14 1.51

Basin 8 1.06 0.00 0.00 1.06 0.07

Basin 9 1.14 0.00 0.00 1.14 -0.07

Basin 10 1.09 0.00 0.00 1.09 0.04

Basin 11 0.00 N/A 0.39 0.39 0.70

Basin 12 0.26 0.00 0.00 0.26 0.13

Basin 13 0.00 N/A 0.00 0.00 0.26

Basin

Monitoring Season (7/23/14 - 11/18/14)

• Average summer and late frontal storms = Wet Summer season

• Stormwater runoff was less than modeled:

• Lower intensity storms

• More upland and channel infiltration?

• System captured and recharged water:

• Detention Basin did not overflow primary outlet structure

• Upstream In-Channel Basins captured the majority of the flow

• All stormwater delivered to the system was captured

• Estimated capture of 36 acre-feet during the monitoring period

• Infiltration trenches and drywells filled and drained rapidly

• 5-7 years of continued monitoring are recommended to capture variability in precipitation:

• Additional data will improve understanding of:

• Rainfall/Runoff relationships

• Efficiency of basins, drywells and infiltration basins

• Groundwater response

• Funding Source Unknown

• Ballpark annual inspection & monitoring costs will be around $55K

• Potential cost savings if

County performs some tasks