Our Projects

Client: The Greens at Ventana Canyon HOA 

Location: Tucson, AZ 

(Project “stats” off to the side): 

1,600 ft of water main 

2,200+ ft of service line 

14 buildings 

120 total units 

Project Overview: 

The Greens at Ventana Canyon condominium homes was experiencing a high frequency of breaks in their water distribution system. Riley conducted an assessment of the current water distribution and determined that poor initial construction practices were the reason for frequent waterline breaks throughout the property and proceeded with a full system redesign. Riley conducted hydraulic modeling of the new system using EPANET and prepared design drawings and specifications. The new system design was updated to meet current drinking water system design guidelines and best practices for operation and maintenance 

Client: ACUITY Environmental Solutions, LLC 

Location: Nogales, AZ 

330 ft of pipe 

150 gpm system capacity 

Project Overview: 

ACUITY Environmental Solutions is providing groundwater remediation services and subcontracted Riley to assist with engineering design of a new groundwater extraction well and pumping system. Riley designed the pump and piping system (civil, mechanical, and electrical) to extract the groundwater and pipe water into the existing treatment system. The new groundwater well serves as an addition to an existing system of remediation wells. The additional groundwater well serves as an upgrade to the existing remediation system, increasing the output of treated groundwater. Riley assisted with the pump selection, pipe sizing, and appurtenance selection to safely convey the flow to the existing equalization tank.  

Client: Chee Family Residence / Ranch Hands Ministry Church 

Location: Leupp, AZ 

6+ buildings 

6000+ feet of waterline 

5500+ feet of sewer line 

Project Overview: 

The access to clean and reliable potable drinking water on the Navajo Nation has been a longstanding issue and has hindered development and growth. To help address these issues at the community scale, Riley is working with community members in Leupp, Arizona to upgrade an existing water well system that was primarily intended for livestock and agriculture use to also include residential potable uses. The new water system design will require retrofitting the existing well, integrating a treatment system and designing the water distribution and wastewater systems. 

Location: Oro Valley, AZ 

10+ Chapters 

Hydrologic runoff computations 

Open-Channel Hydraulic designs 

Scour and Sediment Transport  



Project Overview: 

The Town of Oro Valley stormwater utility department has been experiencing maintenance and repair issues throughout the town’s drainage infrastructure. The Town determined the need to update the drainage criteria manual to account for the unique desert hydrologic conditions such as flash floods and sediment transport. The Town relied up on the experience of Riley’s senior engineers who have extensive experience in southwest desert hydrology & hydraulics and geomorphology to improve upon the current manual by incorporating engineering methods and practices specific to the region.  

Client: Hudbay Minerals (Rosemont Copper Company) 

Location: Pima County, AZ 

(Project “stats” off to the side): 

11.6 square mile watershed 

12 miles of streambeds analyzed 

-19 Rain/Streamflow monitoring sites 

Project Overview: 

The Rosemont Project Watershed Model (RPWM) is a HEC-HMS based watershed model that was created for the Rosemont Copper project in Pima County to comply with requirements set forth by the Arizona Department of Environmental Quality.  The HEC-HMS model uses data from a dense network of sitespecific rain gages and stream gages located throughout the site. The RPWM will be used to estimate potential impacts that the project may have on downstream runoff. Riley is tasked with the calibration and implementation of the RPWM, using site-specific rain and stream gage data to estimate potential impacts and mitigation efforts that the proposed mine development may have on downstream flows. 

Client: Hudbay Minerals (Rosemont Copper Company) 

Location: Pima County, AZ 


44,000+ square feet of survey 

-7 Monitoring Sites 

-LIDAR Surveys 

-Vegetation Surveys 

Project Overview: 

Barrel Canyon and Davidson Canyon are ephemeral regional watercourses in Pima County that are subject to intermittent surface water flows and flashy runoff events. Riley was contracted to conduct baseline surveys of various locations to characterize vegetative and geomorphological conditions (i.e., vegetation strata sampling, photographic record, sediment gradation analyses, LIDAR surveys) prior to the proposed construction of the Rosemont mine. The baseline conditions were assessed on an annual basis to determine if there were any naturally occurring patterns which may be impacted by the mine. 


Client: SRK Consulting 

Location: Arizona 

(Project “stats” off to the side):  

7,000+ ft of channel  

800+ ft of spillway  

3 Spillway Types Evaluated 

3 Channel Armoring Types Evaluated 

18 Total Design Options 

SRK Consulting is providing mining-closure services for a confidential site in Arizona and utilized Riley for designing surface stormwater control structures (i.e., channels, spillways, culverts and stilling basins) associated with reclamation at four sites around the mine. Multiple design options consisting of varying spillway and channel armoring types were evaluated at each of the four sites. The multiple design options included evaluation of a wide range design flows ranging from the 100-year flood event to the Probable Maximum Flood event to minimize risk to the surrounding community while restoring hydrology to pre-mining conditions. Tradeoff analyses were performed, considering factors such as capital costs and risk mitigation, allowing the client could make confident decisions moving forward into final design and construction.   

Client: SRK Consulting 

Location: Arizona 

(Project “stats” off to the side): 

-19 Square miles of watershed 

-8,900+ ft of Channel 

1,500 ft of Spillway 

-48 Spillway Design Options 

176 Channel Design Options 

-240 Total Stormwater Management Options 

An inactive large mining site has significantly altered the natural watercourse and landscape over the course of its mine life. In order to permanently close the site, it must be reclaimed in a manner that is environmentally responsible, restores surface flows to pre-mine conditions, and is safe to the public and surrounding communities. As part of the reclamation efforts, surface stormwater control structures (channels and spillway) are being designed for floods ranging from the 1,000-year event to the Probable Maximum Flood event to mitigate flood risk to neighboring communities. Of particular concern for this project is the increasing uncertainty of climate change which is being accounted for in the design of the stormwater control structures. A multi-criteria analysis matrix was developed to evaluate the feasibility of the design options, providing the client with a safe and cost-effective approach for reclamation. 

Client: Asarco LLC, Mission Complex 

Location: San Xavier District, Tohono O’odham Nation, Arizona 

(Project “stats” off to the side): 

-6,000 ft of Channel and Berm 

-24 Containment Ponds 

-215 acres of floodplain modeled 

24” D50 Rock Riprap Armoring 

Project Overview: 

The natural watercourse of several braided washes caused significant incising and erosion of the existing containment earthworks which led to onsite waste rock stormwater comingling with offsite stormwater. A channel and levee system was designed to contain the waste rock runoff and safely divert offsite stormwater around the waste rock dump. The levee was armored with large riprap to protect against the sedimentladen highly erosive flows that occur onsite. In-depth hydrologic and 2D hydraulic modeling was performed to estimate peak flows and design the levee system. The end product for the client was a cost effective design using on-site materials that complied with requirements set forth in the Section 404 permit issued by the U.S. Army Corp of Engineers.