NYC: Cannonsville Case Study CEE 577 #41 2 1 CEE 577 Lecture - PDF document

CEE 577 Lecture #41 4/17/2013 Updated: 17 April 2013 Print version Lecture #41 TOC & THMFP Models II Scientific Literature CEE 577 #41 1 NYC: Cannonsville Case Study CEE 577 #41 2 1

CEE 577 Lecture #41 4/17/2013 Cannonsville Reservoir Study  Algal & THM Precursor Models  Doerr, Stepczuk and others  Cannonsville Reservoir  Part of Catskill ‐ Delaware Supply for NYC  Dimictic; Eutrophic (impounded in 1965)  P avg = 30 µg/L  Characteristics for 1995  Hydraulics  Loading  H mean = 19 m  TOC = ? x 10 2 kg/yr  V = 373 x10 6 m 3  P = ? x 10 3 kg/yr   mean = 4.7 months  SA = 19.3 x10 6 m 2  DA = 1160 x10 6 m 2 For more, see the literature at: https://www.ecs.umass.edu/eve/research/nyc_chloramines/literature.html CEE 577 #41 3  Inflow  West Branch of Delaware River (WBDR) ~80%  Three outflows  Over spillway  Withdrawal to aqueduct  10, 20** or 37 m below spillway  Release at base of dam CEE 577 #41 4 2

CEE 577 Lecture #41 4/17/2013  Individual models CEE 577 #41 5 Forcing Functions  Lower flows in 1995, resulted in lower loadings CEE 577 #41 6 3

CEE 577 Lecture #41 4/17/2013 PAR  Photosynthetically ‐ active radiation  Often defined as the light between 400 and 700 nm CEE 577 #41 7 CEE 577 #41 8 4

CEE 577 Lecture #41 4/17/2013 SOD  For CEE 577 #41 9 SOD continued  In ‐ situ device CEE 577 #41 10 5

CEE 577 Lecture #41 4/17/2013 Model Performance  Weekly measurement in water column  Objective: monthly average within 2 standard deviations CEE 577 #41 11 Performance II  Systematic depletions of:  Epilimnetic NO x  Hypolimnetic DO  Over ‐ prediction of ammonia? CEE 577 #41 12 6

CEE 577 Lecture #41 4/17/2013 Performance: DO  Progressive depletion of DO in hypolimnion CEE 577 #41 13 CEE 577 #41 14 7

CEE 577 Lecture #41 4/17/2013 Verification  Problem with limited data in 1994 CEE 577 #41 15 Verification CEE 577 #41 16 8

CEE 577 Lecture #41 4/17/2013 Verification CEE 577 #41 17 Performance: Withdrawal CEE 577 #41 18 9

CEE 577 Lecture #41 4/17/2013 Cannonsville THMs: General Info  Major Papers  Stepczuk, Martin, Longabucco, Bloomfield & Effler, 1998  “Allochthonous Contributions of THM Precursors in a Eutrophic Reservoir”, J. Lake & Res. Mgmt., 14(2/3)344 ‐ 355  Stepczuk, Martin, Effler, Bloomfield & Auer, 1998  “Spatial and Temporal Patterns of THM Precursors in a Eutrophic Reservoir”, J. Lake & Res. Mgmt., 14(2/3)356 ‐ 366  Stepczuk, Owens, Effler, Bloomfield & Auer, 1998  “A Modeling Analysis of THM Precursors for a Eutrophic Reservoir, J. Lake & Res. Mgmt., 14(2/3)367 ‐ 378  THMFP Method  Method 5710B of Standard Methods  pH 7.0, 7 days, 25 C, dosed to get >1.0 mg/L residual  Average CV was 4% for field replicates CEE 577 #41 19 1995 Data  Severe Drought  Net production of precursors in Epilimnion is evident from THMFP data Stepczuk et al., 1998, J. Lake & Res. Mgmt., 14(2/3)367-378 CEE 577 #41 20 10

CEE 577 Lecture #41 4/17/2013 Mass Balance Model: THMFP     M W E S     S M W E  Terms  W = allochthonous mass loading From tributaries  autochthon ous  E = mass export by outflow allochthon ous Spill + release + water supply withdrawal   S = net autochthonous production Gross production ‐ decay  Stepczuk et al., 1998, J. Lake & Res. Mgmt., 14(2/3)367-378 CEE 577 #41 21 Mass Balance Model: DOC  Mid ‐ summer drop in S  Not seen with THMFP  Lower average S:W ratio  1.7 for THMFP  0.7 for TOC autochthon ous allochthon ous Stepczuk et al., 1998, J. Lake & Res. Mgmt., 14(2/3)367-378 CEE 577 #41 22 11

CEE 577 Lecture #41 4/17/2013 Mass Balance Model: S  Monthly changes in S  Incremental not cumulative  No apparent correlation between net production of THMFP and DOC  Raises questions about use of TOC as a surrogate for THMFP Stepczuk et al., 1998, J. Lake & Res. Mgmt., 14(2/3)367-378 CEE 577 #41 23 dc       1 V W Q c E ( c c ) V S 1 1 1 1 12 2 1 1 1 dt dc       2 ‐ Layer model 1 V W Q c E ( c c ) V S 2 2 2 2 12 1 2 2 2 dt 0  Spatial resolution  Outflow (Q)  Epilimnion  Separated based on withdrawal location  Designated “1” or “E”  Mixing (E)  Hypolimnion  Designated “2” or “H”  From temperature data  Loading (W)  Net production (S)  Measured stream data  Not directly observed for epilimnion Stepczuk et al., 1998, J. Lake & Res. Mgmt., 14(2/3)367-378 CEE 577 #41 24 12

CEE 577 Lecture #41 4/17/2013 Estimation of vertical Dispersion Coefficient  Use analogous 2 ‐ layer temperature model      T E A     2 12 12 V T T    2 1 2 t z 12   ( t 1 ) ( ) t T T V z  2 2 2 12 E   12   T T tA 1 2 12  Apply measured temperature profiles to get E Owens, 1998, J. Lake & Res. Mgmt., 14(2/3)152-161 CEE 577 #41 25 S 1 & S 2 Fitting S to Data determined by fitting curves to data  Adjust S to match model predictions to data  Keep S at zero S 1 & S 2 equal to 0 CEE 577 #41 26 13

CEE 577 Lecture #41 4/17/2013 Select of S (cont.)  Intermediate option  Fit S 1 to data  Set S 2 to zero  Justification for S 2 =0  No algal growth in hypolimnion  Allochthonous THMFP originally trapped in hypolimnion is recalcitrant Stepczuk et al., 1998, J. Lake & Res. Mgmt., 14(2/3)367-378 CEE 577 #41 27 Mechanistic Model for S  Sub ‐ model for algal FP production   d THMFP    A TTHMFP dt    ( FN )( FL ) A TTHMFP max z   g THMPF R 5   Depends on:  max g Chl day  Algal concentration (A)  from measured Chl (C T )  Light Function  From Microcosm studies  Data fit data to Steele’s Equation  150     E K I I   L Stepczuk et al., 1998, J. Lake & Res.  2 m s z z FL exp 1   Mgmt., 14(2/3)356-368 z   K K CEE 577 #41 28 L L 14

CEE 577 Lecture #41 4/17/2013 Mechanistic Model for S  Sub ‐ model for degradation of THMFP  Independent 1 st order loss terms for autochthonous and allochthonous forms   d THMFP   autochthon ous k THMFP L ( au ) autochthon ous dt   d THMFP   allochthon ous k THMFP L ( al ) allochthon ous dt CEE 577 #41 29 Epilimnion: k L(al) =k L(au) =0.08d -1 Mechanistic Hypolimnion: k L(al) =k L(au) =0.00d -1 Model  Results based on:  Two Scenarios  No decay of any THMFP in hypolimnion Epilimnion: k L(al) =0.00; k L(au) =0.15d -1  No decay of Hypolimnion: k L(al) =0.00; k L(au) =0.15d -1 allochthonous THMFP  Fitted K L values Stepczuk et al., 1998, J. Lake & Res. Mgmt., 14(2/3)367-378 CEE 577 #41 30 15

CEE 577 Lecture #41 4/17/2013 2 ‐ Layer model  Spatial resolution  Epilimnion S 1 & S 2 determined by  Designated “1” or “E” fitting curves to data  Hypolimnion  Designated “2” or “H” dc       1 V W Q c E ( c c ) V S 1 1 1 1 12 2 1 1 1 dt dc       1 V W Q c E ( c c ) V S 2 2 2 2 12 1 2 2 2 dt 0 Stepczuk et al., 1998, J. Lake & Res. Mgmt., 14(2/3)367-378 CEE 577 #41 31  To next lecture CEE 577 #41 32 16