Buil Buildin ding g TR TRUST UST in in Or Oreg egon on Presented by Doug Beyerlein, PE, PH, D.WRE: Clear Creek Solutions Chris Hass, PE: Contech Engineered Solutions Scott Mansell, PhD, PE: Clean Water Services
Intr In trodu oducti ction ons Sc Scott t Man ansell, sell, PhD, , PE Chris Ch is Has ass, s, PE Doug Do g Bey eyerlei erlein, n, PE PE, PH, D.WR WRE Senior Engineer Stormwater Consultant – OR Principal Engineer 503-681-4466 503-807-2322 425-225-5997 MansellS@CleanWaterServices.org CHass@ContechES.com beyerlein@clearcreeksolutions.com
Ag Agenda enda § Intr oduction to TRUST and Continuous Simulation Modeling § Continuous Modeling Example § Applications of TRUST by Clean Water Ser vices
TRUS TRUS T Tualatin River Urban Stormwater Tool § Developed for Clean Water Ser vices. § Includes the entir e Tualatin River Basin.
TRUS TRUS T T Map Map Int Interf erfac ace
TRUS TRUS T § Long-ter m r ain gauges § 1 948-present
TRUS TRUS T TRUST is built on the WWHM HSPF softwar e platfor m. CCS has developed similar stor mwater softwar e for § 1 9 counties in western Washington § Alameda, Santa Clar a, San Mateo counties in SF Bay Area § Sacramento, San Diego, Riverside, Orange counties in Califor nia § City of Salinas, Califor nia § South Korea
Wh Why y TRUS TRUS T? T? 1 . Easy to use. 2. Wide range of BMPs 3. Both water quality and flow control BMPs 4. Fast set up and execution. 5. Has been customized with local data. 6. Continuous simulation hydr ology.
Old S Old S choo chool: l: S S ingle ingl e Even ent t Model odel Single Event Methods: § Rational Method: Q = CIA (1 880s) § SBUH SCS Curve Number s (1 930s) Cr eated pr e-computer . Simplified for calculation by slide r ule. REQUIRES MULTIPLE MAJOR ASSUMPT IONS.
S S ingle ingl e Even ent M t Metho ethod d Assum Assumpt ption ions § Runoff frequency is the same as r ainfall fr equency 00-year flood). FALSE (the 1 00-year stor m causes the 1 § Antecedent soil moistur e conditions ar e always the same. FALSE § Rainfall events ar e never back to back (one stor m immediately after another ). FALSE § Stor m shape and r ainfall distr ibution ar e always the same. FALSE POOR ASSUMPTIONS!!!
S S ingl ingle e Even ent M t Metho ethods ds § Still the cur r ent standard most places in Or egon, but… § Pr oduces stor mwater control facilities that do not pr event incr eased str eam channel er osion. § Pr oduces stor mwater control facilities that do not pr event flooding downstr eam when combined with flows fr om other developed subbasins.
S S ingl ingle e Even vent t Method ethods § Stormwater contr ols sized using single events have § Increased erosion § Matched predevelopment peak only § Large incr ease in dur ation of flows in the erosive r ange. § Caused flooding § Extended per iod of peak flow from from multiple subbasins causes mor e peak over lap downstream § Inaccur ate pr ediction of antecedent antecedent moistur e conditions, precipitation, and back-to-back events https:/ / www.researchgate.net/ figure/ Hydrograph-Analysis-for-Conventional-Detention-of-the-Two-Year-2-h-Event-in-Fort_fig1_318613692
A Be A Better er Way: y: Con Contin tinuo uous us S S imula im ulatio tion S S tor tormwater er Met Metho hods § Runoff frequency is statistically calculated from the long-term hourly simulated r unoff data. § Antecedent soil moistur e conditions ar e calculated (and change) ever y time step. § Rainfall & evaporation are from the measur ed histor ical r ecor d. § Stor m shape and r ainfall distr ibution ar e fr om the measur ed histor ical r ecor d. § Calibr ation to r eal stor ms and r eal str eamflow data Bad assumptions fr om single event methods ar e gone!
His History tory of of HS HS PF PF Mod Model el & & TRUS TRUS T T S S oftw oftwar are § 1 966: Stanfor d Water shed Model § 1 979: EPA HSPF § 2001 : Western Washington Hydr ology Model (WWHM) § 201 5: T RUST § 201 9: TRUST 201 9 (update of or iginal T RUST)
HS HS PF PF § Continuous simulation hydrology computes the entir e hydr ologic cycle for multiple year s. § Multiple-year hour ly histor ic rainfall used to gener ate gener ate multiple-year hour ly hour ly r unoff data. § Stormwater runoff = surface runoff + inter flow.
TRUS TRUS T § Continuous simulation computations from HSPF (included in T RUST softwar e). § HSPF r uns in the backgr ound with local calibr ated par ameter values and meteor ological data. § HSPF sponsor ed and funded by EPA and USGS.
TRUS TRUS T § Continuous simulation hydrology to compute stormwater r unoff for both conditions. § Models & sizes BMPs to mitigate development effects Pr edevelopment Post-development
TRUS TRUS T § T he entire water cycle is computed on an hourly time step for multiple year s. § T RUST computes changes in soil moistur e, evapotranspir ation, and r unoff ever y time step. § T hr ee types of r unoff: § Sur face r unoff § Interflow (shallow subsurface r unoff) § Gr oundwater / base flow § Can automatically size and compute r outing thr ough a number of types of BMPs.
TRUS TRUS T § Flow contr ol standard based on er osive flow range. § Flow contr ol standard is typically ½ of 2- year to 1 0-year flow. § Adjustable within TRUST for differ ent jur isdictions / differ ent applicable range.
TRUS TRUS T § Flow Dur ation Analysis: Per cent of time the flow exceeds a specific value over simulated per iod. § Requir es continuous simulation hydr ology.
Con Continu tinuou ous s Simul Simulation tion with with TRUS TRUS T § Pr oduces stor mwater control facilities that ar e cor r ectly sized because: § Pr edevelopment par ameter values are calibr ated to local hydr ologic conditions and land uses. § Runoff calculations ar e mor e accur ate due to better antecedent moistur e conditions and r eal, measur ed stor m events. § Pr edevelopment flood fr equency values ar e accur ate because based on flow, not pr ecipitation and based on r eal storms. § Stor age volumes to r educe flows to pr edevelopment conditions ar e mor e accur ate because they have been ‘tested’ over many year s in the model.
Con Continu tinuou ous s Simul Simulation tion with with TRUS TRUS T § Pr oduce stor mwater contr ol facilities that do not incr ease stream channel er osion because: § Match pr edevelopment flow durations in the er osive flow range in the str eam instead of peak flows. § T he number of hours of high (erosive) flows in the stream do not incr ease above pr edevelopment conditions.
Using TRUST Using TRUST § Dr ainage ar eas ar e divided into per vious land segments § Soil § Vegetation § Slope § Imper viousness § Per vious and imper vious segments ar e linked to r outing and LIDA, e.g. § Extended dr y basins § Constr ucted water quality wetlands § Rain gar dens § Por ous pavement
Using Using TRUST TRUST § User locates pr oject on Tualatin Basin map, inputs pr e- and post-development land use and pr oposed mitigation measures. § Pr edevelopment and mitigated flows ar e compar ed at Point of Compliance (POC). § Mitigation measur es designed to meet flow contr ol standar d and/ or water quality tr eatment standard.
TRUS TRUS T Routi T outing ng/S /S tor orag age e Elem Elemen ents ts 1 . Extended Dr y Basin 2. Constr ucted WQ Wetland 3. Natur al Channel 4. Gr avel Tr ench/ Bed 5. Flow Splitter 6. SSD Table 7. Stor age Tank 8. Stor age Vault
TRUS TRUS T LIDA T LIDA Elem Elemen ents ts 1 . Rain Gar den 2. LIDA Swale 3. Infiltr ation Planter 4. Flow-T hr ough Planter 5. Por ous Pavement 6. Gr een Roof
TRUS TRUS T Each element is visually represented on the Schematic screen with all of the linkages between elements shown.
TRUS TRUS T User has complete control of TRUST element input data.
Ag Agenda enda § Intr oduction to TRUST and Continuous Simulation Modeling § Continuous Modeling Example § Applications of TRUST by Clean Water Ser vices
Pr Project oject Ex Examp ample le Ov Overview erview § Pr e-developed Condition § Select location § Use NRCS for soil type § Set up basin ar ea § Post-developed Condition § Alter imper vious/ per vious ar eas to r eflect development § Run fir st iter ation of pond § Optimize pond sizing § Autopond sizing § Summar y
Pr Project oject Ass Assump umptio tions ns § Develop apar tments on tax lot 9000, 91 00 and 9200 § Pr e-developed Condition § Pasture 3.92 acr es § Post-developed Condition § 74,300 sqft (1 .70 acr es) r oof § 45,1 00 sqft (1 .04 acr es) parking § 51 ,400 sqft (1 .1 8 acres) landscape § Development tr igger s Categor y 3 or NMFS City of Beaverton GIS S ystem r equir ements for flow-dur ation cur ve matching BMP
Pr Project oject Ex Examp ample le Loc Locati ation on
Pr Pre-De e-Devel velop oped ed Con Conditi dition on § All vegetation assumed to be pasture. § Use NRCS to classify soil types. Type C/ D US DA National Resource Conservation S ervice Websoil S urvey
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