Master of Science, Utah State University, 1977, Watershed
Science

Bachelor of Science, State University of New York at Cortland,
1969, Geology

Professional Hydrologist - American Institute of
Hydrology

Certified Erosion Control Supervisor - Colorado
Department of Transportation

American Institute of Hydrology

American Water Resources Association

Association of State Floodplain Managers

Colorado Association of Stormwater and

Floodplain Managers
- Chairman, Flood Committee

International Erosion Control Association

Flow Technologies, Breckenridge, Colorado

- Owner/Professional Hydrologist

- (1996 - present)

U.S. Bureau of Reclamation, Denver, Colorado

- Hydraulic Engineer

- (1982 - 1996)

U.S. Geological Survey, Denver, Colorado

- Hydrologist

- (1979 - 1982)

U.S. Bureau of Land Management, Sacramento, California

- Hydrologist

- (1977 - 1979)

Mr. Trieste is a registered Professional Hydrologist specializing in river hydraulics and hydrology. Areas of expertise include hydrologic studies, flood control planning and design, drainage, dam safety and dambreak analyses, dam hydraulics, and hydraulic structures. He owns Flow Technologies formed in 1996. Mr. Trieste has previously worked as a hydraulic engineer with the U.S. Bureau of Reclamation, Denver, Colorado, focusing on safety of dams, dam hydraulics, and large floods, the U.S. Geological Survey, Denver, Colorado, as a research hydrologist developing rainfall/runoff models, and for the U.S. Bureau of Land Management as District Hydrologist, Folsom, California, focusing on watershed management and non-point source pollution.

Mr. Trieste is very active in the Colorado Association of Stormwater and Floodplain Managers and is Chairman of the Flood Committee.

Lead hydraulic engineer for safety of dams hydraulic evaluations including dambreak/inundation studies, inundation map preparation, hazard classifications, and dam modifications on hundreds of dams nation-wide. Considerable work was done on designing spillways and outlets, and reservoir sizing to accommodate new design floods. Reservoir operating procedures were modified or developed to allow for safe operation of dams, and to optimize water use for irrigation, power generation, recreation, industrial, and domestic purposes.

Instrumental in developing Bureau of Reclamation’s procedures for performing dambreak/inundation studies, author of Reclamation’s Downstream Hazard Classification Guidelines, and contributing author of Reclamation’s Design of Small Dams.

Part of a team of expert meteorologists and hydrologists working to evaluate the U.S. Army Corps of Engineers 1996 Probable Maximum Precipitation study for Cherry Creek Dam safety evaluation. Study involves evaluating historic peak discharge records and on-site paleohydrology evidence on selected sub-basins within Cherry Creek Basin for largest known peak discharges. Rainfall/runoff modeling is used to estimate the rainfall amounts and distributions necessary to drive the peak discharges. Multi-disciplinary study involves interfacing with State appointed Technical Review Committee at quarterly intervals.

Performed research on the USGS Precipitation Runoff Modeling System. Study involved watersheds in Colorado coal basins. Collected hydrometeorological data including rainfall, snow depth, evaporation, streamflow, etc. Developed and tested computer algorithms for computing watershed physical processes, calibrated models, and applied models to historic meteorologic data to simulate historic flow where records were non existent. Applied models to predict impacts of mining on hydrology of watersheds.

Downstream hazard classifications were performed on several embankment dams. Project involves collecting data and information, dambreak/inundation modeling, and assigning a hazard classification to the dams based on Department of Interior criteria.

Problems with the existing flood control system, and causes of flooding were evaluated. Identified a realistic design flood, and proposed several flood control alternatives weighing cost against flood protection. In addition, flood control alternatives were combined with stream rehabilitation measures for the purpose of fish habitat improvement which is a very sensitive issue in the region. Study involved working with and obtaining input from many organizations including Army Corp of Engineers, National Resource Conservation Service, State and local agencies, Universities, and the general public.

Developed program to inventory non-point sources of pollution on BLM land in California, and to design and implement Best Management Practices.

Responsible for BLM watershed management activities in District. Included monitoring water quality and runoff changes for different land uses, non-point source pollution and control, designing hydraulic structures, implementing Best Management Practices, supervising staff, and coordination with multi-disciplinary teams.

Hydrology studies, drainage plans, and a SWPPP for a new road were performed. Data was collected including soils, vegetation, existing hydrology studies, and adjacent drainage plans. Hydrologic and hydraulic analyses were done for ditch and culvert sizing and design, and detention needed to mitigate increased runoff. The SWPPP is commensurate with EPA regulations and involves drawings before, during, and post construction, completed detail sheet of recommended Best Management Practices including timing and placement, completed detail sheet of inspections and maintenance requirements, detailed information on vegetation establishment with time schedule for installation.

Lead Bureau of Reclamation engineer for hydraulic and hydrologic investigations on impacts of proposed operational flow changes to Truckee River. Involved analyzing river morphology, aggradation/degradation, streambank erosion, Pyramid Lake delta formation, and Lake Tahoe shore erosion for Truckee River Operating Agreement Environmental Impact Statement. Worked on EIS team to write and publish EIS and respond to public comments.

A Phase III drainage plan has been completed that meets criteria set forth in the Douglas County Storm Drainage Design and Technical Criteria manual. The site was divided into sub-basins and hydrologic and hydraulic analyses performed for peak discharge, roadside ditch and culvert sizing, and detention pond location, sizing and design. Alternatives for levees and channelization were evaluated and designed for Baldwin Gulch to mitigate potential impacts from an existing dam located on the property. Auxiliary drainage ditches were designed for the channel along steep slopes, and permanent erosion control alternatives evaluated including riprap, check dams, and synthetic material. A sediment and erosion plan was presented for the construction period.

Perform urban hydrology study, existing drainage structure analysis, and new structure design for all of the City of Del Mar. Purpose was to determine drainage problems, and develop solutions for preventing erosion of bluffs (caused by inadequate drainage) and consequent threat to railroad along Pacific Ocean.

Performed erosion control inspections, erosion control plans, and developed Best Management Practices on construction sites. Work was commensurate with State of Colorado Department of Health, U.S. Environmental Protection Agency, and City of Aurora criteria.

A reach of Baldwin Gulch, Colorado that is part of a Federal Insurance Rate Map (FIRM), has been developed and channelized. Changes to water surface elevations and floodplain widths for 100 - and 500 - yr floods were modeled and compared with existing conditions per FEMA criteria. The existing reach was surveyed to obtain cross-sections and a topographic map. Detailed water surface profile analyses were performed using HEC-RAS. Studies and materials were prepared to meet requirements of FEMA’s LOMR process..

Fill-placement of landfill has been occurring across a natural channel. The Douglas County Engineer determined that such is not permissible and a by-pass channel with a 100-yr flood design discharge shall be constructed across the fill and into the existing channel. That involved determination of design discharge and hydraulic design of a by-pass channel, erosion control plan for slopes up to 33 percent, and design drawings

River water surface profile hydraulic analyses based on HEC-RAS, and floodplain mapping was performed for construction of a stream crossing. Water surface profiles from existing Urban Drainage and Flood Control District study were duplicated for the purpose of comparing impacts of road crossing on UDFCD’s designated 100-yr floodplain.

The 100-yr floodplain was delineated for Running Brook Estates, located in Elbert County Colorado, based on hydraulic analysis using HEC-RAS. A comprehensive hydrologic investigation was performed for estimating the 100-yr discharge due to lack of stream gage data, and discrepancy and controversy over methods used to estimate flood frequency discharge in the region of Running Creek Basin. Methods used in the evaluation included rainfall/runoff modeling, regional regression, and paleohydrology.

Property was planned for development that contains a National Resource Conservation Service flood control dam located in Parker, Colorado. With regard to development impacting the dam, the Office of the State Engineer has requested an analysis to determine effect on the dam’s passing the 100-yr flood. The 100-yr flood for both historical and developed conditions was derived from CUHP (Colorado Unit Hydrograph Procedure) and routed through the dam. Elevation-storage, and elevation-discharge relationships were developed for the reservoir, and outlets and spillway, respectively. Reservoir routing was performed via HEC-1.

A dambreak/inundation study necessary to mitigate development of property downstream from Franktown Parker - B1 Dam, located near the town of Parker, Colorado, was performed. That included determining the discharge that could overtop and fail the dam, the recurrence interval of such discharge, modeling a hypothetical dam failure, and determining the area subject to flooding including flood depths and velocities. BOSS DAMBRK and HEC-RAS models were used to perform the analyses.

Kiowa School District, Colorado, planned to expand facilities including an addition to the existing school and construction of an adjacent building. Investigations were performed which included hydrology studies based on HEC-1 to define frequency floods, and water surface profile studies based on HEC-RAS.

Private property located immediately downstream from The Greens at Cedar Ridge subdivision near Tulsa, Oklahoma, is experiencing erosion and sediment damage due to excessive runoff emanating from the subdivision. The property owner, knowing that the problem didn’t exist prior to the subdivision, has filed a law suit against the developer and engineering firm. Obtained data, information, and study reports used in the drainage plan for The Greens and scrutinized analyses and results. Testimonial information is being prepared for an upcoming court case.

Trieste, D.J. (1994), "Supercritical/Subcritical Flows in Natural Channels." Proc 1994 Conference, Hydraulic Engineering, 731-736, ASCE

Trieste, D. J. (1992). "Evaluation of Supercritical/Subcritical Flows in High Gradient Channel." J. Hydr. Engrg., ASCE, 118(8), 1107-1118.

Trieste, D.J. (1988). Downstream Hazard Classification Guidelines. Assistant Commissioner - Engineering and Research Technical Memorandum No. 11. US Bureau of Reclamation.

Design of Small Dams, Contributing Author, Chapter 13, Dam Safety, US Bureau of Reclamation, Third Edition, 1987.

Trieste, D.J., and Jarrett, R.D. (1987). "Roughness Coefficients of Large Floods." Proc. Conf. Irrigation Systems for the 21st Century, 32-40, ASCE.

Trieste, D.J. (1995). "Manning's Equation and the Internal Combustion Engine," Proc. of 1st International Conf., Water Resources Engineering, Amer. Soc. Civil Engineers, San Antonio TX, Vol. 1, pp. 76-78.