Flood Control District of Maricopa County (FCDMC)

Project included developing alternatives for the overall rehabilitation or replacement of Buckeye FRS No. 1 to identify and select a preferred alternative that addresses the dam safety concerns. Dr. Unnikrishna conducted several analyses and modeling studies, supervised junior engineers and prepared several technical reports as part of this project. Analyses include: Pacific Southwest Inter-Agency Committee (PSIAC) sedimentation analysis; review of Hassayampa River downstream impacts; calculations to estimate the Probable Maximum Precipitation (PMP) for 6- and 72-hour durations based on the National Weather Service (NWS) HMR-49 procedures for the various dam alternatives; using PMP depth estimates, obtained Probable Maximum Flood (PMF) estimates using HEC-1 models; supervised and conducted unsteady HEC-RAS hydraulic modeling to size the emergency spillways for two new dam alternatives to maintain the crest elevations at the 1000-year 24-hr water surface elevation and to determine the top of dam required for the dam alternatives upstream of the emergency spillway and principal outlet. Developed HEC-RAS models to size the drop structure downstream of the new emergency spillways for two new dam alternatives. The following article was published from this project: Unnikrishna, P., and I. Thomas, Preferred alternative selection for the Buckeye FRS 1 dam rehabilitation project, in Proceedings of the 2009 Annual Water Symposium: “Managing Hydrologic Extremes”, Arizona Hydrological Society and the American Institute of Hydrology, pages 252 – 261, Scottsdale, Arizona, August 30-September 2, 2009.

U.S. Army Corps of Engineers, Fort Worth District.

Managed drainage analysis and production of drainage reports in support of the U.S. Customs and Border Protection (US-CBP) Secure Border Initiative (SBI) Tactical Infrastructure (TI) projects at various locations in Texas, Arizona, New Mexico, and California. These included the pedestrian fence PF-225, vehicular fence VF-300 and access roads. Conducted reviews of hydrologic and hydraulic analysis, and scour and erosion calculations. Hydrologic calculations followed rational, TR-55 and regression approaches. Hydraulic calculations included HEC-RAS, FlowMaster, CulvertMaster, among others. Technical reviews ensured that upstream water surface elevation increases in washes at fence crossings complied with USIBWC regulations.

U.S. Army Corps of Engineers, Fort Worth District. 

The Morley tunnel and Grand tunnel extend for a considerable length north and south of the De Concini Port of Entry in Nogales. These tunnels built around the 1930s cross the International Border and convey flows from Sonora, Mexico and Nogales to the Nogales Wash, which flows north to join the Santa Cruz River. Participated in field visit to collect data and drafted analysis methodology for evaluating hydraulic impacts resulting from proposed vertical swing gates in the two tunnels for the US-CBP and the U.S. Army Corps of Engineers (USACE). Developed HEC-RAS (version 4.1.0) hydraulic models for the tunnels using as-built data provided by USIBWC.

Arizona Department of Transportation (ADOT) Project.

Quality Assurance and Quality Control of Loop 303, a brand new interim four-lane divided expressway from Lake Pleasant Parkway to I-17. Performed the technical review of the hydraulic analysis and scour calculations. Prepared a draft levee operations and maintenance (O&M) manual for ADOT.

Clark County Department of Development Services (CCDDS), Nevada 

Conducted several drainage studies and obtained concurrence from the municipality. These include: Ries Elementary School, Judi Steele Elementary School, Sonata 2, University of Phoenix, Cactus Hills Estates 1 Update, Cactus Hills Estates II Update, Cactus Hills Estates III, Schorr Elementary School, Highlands Ranch 6 Phase 1, Clark County Water Reclamation District Central Plant South Secondary Facilities Phase II, Wilbur & Theresa Faiss Middle School.

 City of Henderson, Nevada Approvals,

Conducted several drainage studies and obtained concurrence from the municipality. These include: Athens Road, Athens School/Park, Canyons at McDonald Ranch (Parcel C/D, Parcel B, Parcel H, Parcel R), Horizon Irrigation, Lake Las Vegas, Silverado Court 3 Phase 2, Silverado Court 5, Tuscany Parcel 5, Tuscany Parcel 6A, Tuscany Parcels 23 & 25 (conceptual for Parcel 22), Vantage 1 Lofts and Flats, Smalley Elementary School.

Clark County Regional Flood Control District (CCRFCD), Nevada, Concurrence,

Conducted several drainage studies and obtained concurrence from the municipality. These include: Athens Road, Athens School/Park, Horizon Irrigation, Johnston Middle School, Provance East, Silverado Court 5, Sonata 2, Tuscany Parcel 6A, University of Phoenix, Vantage 1 Lofts and Flats, Wilbur & Theresa Faiss Middle School, Southern Highlands High School.

Silverado Court IV, CLOMR, Clark County, Nevada

Project investigation and management including analysis, site visits, development of portions of the HEC-RAS and WSPG models, conducted technical review and finalized the technical drainage study report preparation including addressing FEMA review comments. Information from previous technical drainage studies (TDS) was used for the Conditional Letter of Map Revision application to FEMA for a Las Vegas Valley Flood Control Master Plan Update (MPU) facility along the Pittman Wash. The original open channel MPU facility was modified to a proposed facility consisting of two 12′ wide by 10′ high reinforced concrete box culverts, 2000 feet long, conveying up to 5,500 cfs into the Cactus Detention Basin. Upstream earthen channel HEC-RAS model results were linked to a Water Surface Pressure Gradient (WSPG; Civil Soft Version 1.2) model extending over the length of the proposed culvert. The study was conducted in accordance with the criteria set forth by Clark County Regional Flood Control District (CCRFCD) and FEMA National Flood Insurance Program (NFIP) requirements.