Mine Reclamation Applications of a New Water Budget Model: Wetbud W. Lee Daniels Dept. of Crop & Soil Environmental Sciences http://www.landrehab.org/WETBUD
Who’s doing what? Zac h Agioutantis, Univ. of Ke ntuc ky - - Pr ogr amme r & MODF L OW W. L e e Danie ls, Vir ginia T e c h - - Pr ogr am c oor dinator & gadfly Be n Hiza, Old Dominion Unive r sity – Julie Me tz mode ls / gr oundwate r Ste phe n Stone , Old Dominion Unive r sity – Huntle y Me adows mode ls T e ss T hompson, Vir ginia T e c h – Sur fac e wate r & E T e stimator s Ric h Whitte c ar , Old Dominion Unive r sity – Gr oundwate r & MODF L OW Pr e vious Gr aduate Stude nts: Ke r by Dobbs, Matt Gloe , John Mc Cle od, E r ic Ne uhaus, O. Wave r ly Par ks, Candic e Pie r c y, T r ac y T hor nton, Cal Smith Re se ar c h Assoc iate s/ Spe c ialists: Dan E vans, Katie Hae r ing, Sar a Klopf and L aur a L e hman.
Objectives • Review brief history of “water budgeting issues” for wetland creation in the mid-Atlantic region of the USA. • Describe the development and basic structure of our new water budget model – Wetbud • Provide an overview of Wetbud’s data requirements, functions and outputs that are potentially useful for mining applications.
Aylett Sand & Gravel Mine in October 1998 Results in Daniels et al. (ASMR 2002)
Western portion of site in April of 1999 following revegetation. Site was chosen as potential for building created wetlands for mitigation of impacts to widening of US 460 (never happened).
Created Wetland Water Budgeting • Wide variation in water budgeting approaches among agencies and consultants. • Many agencies follow and/or recommend variations of the “Pierce Approach” whereby ground water flux is presumed minimal, ET is estimated via Thornthwaite, runoff additions are estimated via SCS/NRCS Runoff Curve Number Method, water is presumed to be detained over the site via a berm, and water level is controlled via an outlet, etc.
Fort Lee Water Budget Studied by USGS & Virginia Tech in late 1990’s. Well REF3A S. Poorly Well Drained 7-4 Wet/Ponded > 20 wells/piezometers monitored for > 2 years along with direct measurements of all water budget components.
Hydroperiod of created soil vs native soil at Ft. Lee; the mitigation site soil was dominated by fac upland vegetation. Only ~20% of the site was characterized by this type of hydroperiod .
(Daniels et al., 2000) 98 cm of 90 cm of ET Out rain In Precipitation (dry year) Evapotranspiration 35.43 in 90 cm In35 (89.99 cm) 38.32 in (97.36 cm) 80 cm of 10 cm of runoff out runoff In Ft. Lee Wetland Surface Out Surface In May 1, 1998 to April 30, 19 99 4.08 in 32.14 in (10.36 cm) (81.64 cm) Net Loss of 0.01 in (0.30 cm) Net Groundwater In Net Groundwater Out 132 cm of 55 cm of 21.29 in 52.24 in GW In GW Out (54.08 cm) (132.69 cm)
Wetland creation site in mineral flat or pocosin type landform. Here, designers presumed that excess rainfall vs. ET + minimal infiltration losses would drive the annual water budget. Before adjustments were made, this site was “too dry” in summer, but very wet in the winter.
A c ommonly e mploye d “simple ” wa y to c re a te a mitig a tion we tla nd is to c re a te a pe rc he d syste m Ca n work on hilltops with low pe rme a bility inte ntiona lly c ompa c te d subsoils Precipitation Evapotranspiration Outflow Inflow X Groundwater a ssume ne g lig ible
Surface soil from an anonymous 3- year old mitigation wetland. Note massive structure in surface breaking to firm plates at about 20 cm. This is the “traffic pan” that was designed to perch the water table, but also led to extremely dry summer conditions.
Water Budget Model Issues Addressed by Wetbud “Ba th T ub ” vs. Slo pe d Syste ms Ve g e ta tive F lo w Re sista nc e Gro undwa te r I nputs vs. da ta ? Ove rb a nk F lo w Co ntrib utio n Whic h Pre c ipita tio n Da ta ? Va ria tio ns in E T E stima to rs Co mple x to po g ra phy
Database (includes PRELOADED raw climate data for 14 VA Weather Stations) We tbud is mass balanc e base d wate r budge t mode l that r uns in a PC e nvir onme nt (No Mac ve r sions ye t!)
We tb ud Ba sic Ve rsio n We tb ud is a de sig n to o l fo r we tland c re atio n Ppt E T SW in SW out Str e am Soil Pe rm. (Ksa t) GW in GW flux mo de le d via Dar c y flo w appr o ac h GW out assuming uphill he ad data available
GSOD Dry/Normal/Wet year calculations. Procedure version 2014-11-22 Precipitation Data based on NOAA/GSOD Station: 724010 Wet / Dry / Normal Splits based on WETS Station: VA7201 Data set examined: From year: 1973 Data set examined: To year: 2014 User input: Minimum accepted year: 1973 Dry Year Maximum Precipitation (in): 39.56 We tbud will auto Wet Year Minimum Precipitation (in): 46.79 Records in the 30% Dry split (sorted by precipitation): 9 Year in the 30% Dry split: 1:2001-->32.29 download e ithe r Year in the 30% Dry split: 2:1997-->34.03 ... ne ar e st or c hose n Records in the 40% Normal split (sorted by precipitation): 13 Year in the 40% Normal split: 1:1981-->39.91 Year in the 40% Normal split: 2:1986-->41.75 NOAA we athe r ... Records in the 30% Wet split (sorted by precipitation): 20 station data and the n Year in the 30% Wet split: 1:1977-->46.86 Year in the 30% Wet split: 2:1983-->47.56 Year in the 30% Wet split: 3:2004-->48.33 c hoose the typic al ... -------------------------------------- We t, Dr y and Nor mal Starting calculations for the Dry year Records in the 30% Dry split: 9 Median in the 30% Dry split: 5 ye ar s out of the last Checking year: 1976 in slot: 5 Dry Spring Check: Score for Month: 3 is 1 30 via an inte r nal Dry Spring Check: Score for Month: 4 is 1 Dry Spring Check: Score for Month: 5 is 1 Dry Spring Check: Score for Month: 6 is 1 algor ithm that has Dry Spring Check: Total Score: 4 Spring is Dry: Year Accepted: 1976 be e n ac c e pte d by ----------------------------------------- Starting calculations for the Normal year Records in the 40% Normal split: 13 USCOE and VA DE Q. Median in the 40% Normal split: 7 Checking year: 1990 in slot: 7 Normal Spring Check: Score for Month: 3 is 2 Normal Spring Check: Score for Month: 4 is 2 Normal Spring Check: Score for Month: 5 is 2 Normal Spring Check: Score for Month: 6 is 3 Normal Spring Check: Total Score: 9 Spring is Normal: Year Accepted: 1990 --------------------------------------
Note that this is anothe r c r e ate d we tland in a sand & gr ave l mine . De signe r s he r e ignor e d GW and most of it tur ne d into an ope n wate r syste m Wetbud is freeware and available for download at www.landrehab.org/WETBUD
Basic Model via the Wizard • Automatically downloads nearest applicable weather station data (30 years) in Virginia from 15 pre-selected locations and populates ppt and ET estimators for W-N- D years. Will download other data for other states, but “data clean-up” is required. • In Wizard mode, assumes no overbank and GW input; assumes GW losses at 1”/month. • User inputs wetland and watershed size and runoff CN. • Model runs in < 5 minutes once simple inputs are made. Daily time-step but results are charted monthly.
We tb ud Ba sic Ve rsio n We tb ud is a de sig n to o l fo r we tland c re atio n Ppt E T SW in SW out Str e am Soil Pe rm. (Ksa t) GW in GW flux mo de le d via Dar c y flo w appr o ac h GW out assuming uphill he ad data available
Water Budget for Normal Year: 1998 20.00 .00 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec -20.00 Current Fill Precipitation -40.00 Water level (in) Runoff PET-Thornthwaite GW-OUT Outflow -60.00 Net Gain/Loss 50 a c re wa te rshe d ; 5 a c re Actual Water Level we tla nd ; CN = 70 -80.00 F o r this run, no “flo o r” o r E T e xtinc tio n de pth wa s se t, so the mo de l just -100.00 c o ntinue s to c ra nk the wa te r ta b le do wn. -120.00
2 nd mo de l run with muc h la rg e r wa te rshe d ; sma lle r we tla nd , CN = 85 a nd da ta fo r a we t ye a r sho wn.
We tbud Advanc e d Ve r sion Allows for 3- D mode ling inc luding multiple wa te r/ soil/ substra te la ye rs, slope s, va ria ble we tla nd topog ra phy, e tc . Inc orpora te s more rig orous g roundwa te r flux mode ling via MODF L OW (ba sic mode l use s a simplifie d Da rc y a pproa c h) Ge ne ra te s da ily mode ls of wa te r surfa c e topog ra phy in 3D or for a ny c ross- se c tion. Will g e ne ra te de ta ile d hydrope riod pre dic tion for a ny loc a tion in we tla nd.
We tBud – Adva nc e d Ve rsio n Ppt E T SW in Stre a m GW o ut GW in
Model and Component Validation & Calibration Huntle y Me a do ws – F a irfa x (de taile d E T x 4 and GW studie s) No rthfo rk Ba nk – Ha yma rke t (b asic mo de l + o ve rb ank flo w) Ce da r Run 3 – W. o f Qua ntic o Othe rs a t Julie Me tz, Be nde r F a rms, Po c a ho nta s, e tc . AA
Useful Mining Applications • Will automatically download NOAA weather data from nearest station (need to clean up zeros etc.) • Built in algorithm will choose W-N-D years from last 30 years of complete data • Automatically calculates monthly (Thornthwaite) or daily (Penman) ET
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