Catchment Impacts on Hydrology & Water Quality Graphics - PowerPoint PPT Presentation

Te Waikoropupū Catchment Impacts on Hydrology & Water Quality Graphics accompanying summary evidence of Andrew Fenemor for Tasman District Council

A p r i l 1 8 T I T L E G O E S H E R E P A G E 2 Hydrology

3 Flow Modelling Compartments for the AMA

4 TDC groundwater records, Takaka Valley, 1981-2015 Takaka Groundwater Levels 50,000 Sowman 45,000 40,000 Hamama GW level elevation (mm amsl) 35,000 30,000 Jefferson Grove Orchard 25,000 Bennett Savage Ball 20,000 Pupu main spring Cserney 15,000 Motupipi Substation 10,000 Firestation TDC offices 5,000 0 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 Date (1 Jan yyyy) Takaka Fire 2 (23648) TDC Office (6339) Pupu Main Spring (6013) Savage (6713) Sowman (6912) Takaka Firestation (6535) Cserney (6418) Jefferson (6829) Hamama (6710) Motupipi SubStn (6413) Ball (6011) Bennett (6815) Grove Orchard (6224)

5 Modelled and measured flows, Te Waikoropupū Springs, 1999-2015 AMA Groundwater Discharge Springs River (Main Spring + Fish Creek - Salmon Farm) 24 22 20 Groundwater discharge (m 3 /s) 18 16 14 12 10 8 6 4 2 1999 2001 2003 2005 2007 2009 2011 2013 2015 Year Modelled Measured

6 Modelled periods when Takaka River was dry, 2010-2014: blue = fully flowing; white = partly dry Prediction of Full-Length Flow in the Takaka River Partial-length flow days per year ~ 90 days ~ 160 days (to 31 Dec '14) ~ 170 days ~ 190 days ~ 180 days 1 0 Jun-10 Jun-11 Jun-12 Jun-13 Jun-14 Date (1 Jan yyyy)

7 Relative AMA recharge from rainfall vs river leakage, 1980-2015 Average Groundwater Recharge (Exponentially Weighted Moving Average) 32 30 28 26 24 22 Recharge (m 3 /s) 20 18 16 14 12 10 8 6 4 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 Date (1/1/yyyy) Land surface recharge Average land surface recharge River recharge Average river recharge

8 Changes in flows from Te Waikoropupū Springs for 4 land use scenarios Modelled flow statistics for various scenarios for the period 1990-2014 (unless otherwise stated) Hypothetical No Consumptive Current State Double Current Current Scenario No Development Measured Water Takes River (Calibration) Irrigation Scenario WITHOUT Cobb Scenario Scenario Dam Average (l/s) 9,910 9,740 9,910 9,560 8,890 8,480 Main Spring (synthesised by TDC) 3,390 3,060 3,110 3,000 2,810 2,470 Fish Creek 7-day MALF (l/s) 7,290 7,250 7,490 7,010 6,320 5,950 Main Spring (synthesised by TDC) 570 530 640 430 290 230 Fish Creek Zero-flow days (average/year) 0 0 0 0 0 0 Main Spring (synthesised by TDC) 0 1 0 3 6 6 Fish Creek 1 in 10 year low flow (l/s) (2009/10 season) (approximate) 5,985 6,110 6,370 5,850 5,320 5,050 Main Spring (synthesised by TDC) Fish Creek 35 65 180 45 45 10

9 Water Quality (Nitrate-Nitrogen)

1 0 Groundwater Nitrate by Water Body 2006-2016 (from J Thomas evidence Fig 14)

1 1 River nitrate-nitrogen concentrations for Takaka River at Harwood’s and Kotinga Surface Water Nitrate-Nitrogen Concentrations 0.50 0.45 0.40 F e n e m o r S u m m ar y - G r ap h i c s Nitrate-nitrogen concentration (g/m 3 ) 0.35 0.30 0.25 0.20 0.15 0.10 0.05 0.00 1984 1988 1992 1996 2000 2004 2008 2012 2 6 A p r i l 2 0 1 8 Date (1 Jan yyyy) Harwood Kotinga

Soil water holding capacity red and orange are more gravelly so hold less water before they ‘leak ’ Unmapped = hill country (low WHC; 40 mm assumed)

1 3 Current and proposed (waiting list – in pink) irrigation water permits Irrigation scenarios modelled Ha Irrigation Scenario in the AMA Ha irrigated dryland Recharge Zone dairy dairy Current State 993 2063 Current+Proposed Irrigation 1462 1594 Current +Proposed+Plausible 2045 1011 Current+Proposed+Plausible+Unlikely 3056 0 766 l/sec AMA recharge zone water take 1544 1512 allocation limit (one of the FLAG options) Double current irrigation 1986 1070 100% dryland dairy 0 3056 No Development - AMA recharge zone 0 0

Scenario Calculated AMA Fully Mixed 1 4 Nitrate Concentrations (g/m3) Modelled nitrate from Te Waikoropupū Springs for 7 Current Dairy 0.41 0.44 Current+Proposed 0.47 Current +Proposed+Plausible land use scenarios 0.54 Current+Proposed+Plausible+Unlikely 766 l/sec upper allocation limit from 0.44 FLAG deliberations 0.47 Double current irrigation 0.35 100% dryland dairy 0.002 No Development - AMA recharge zone Nitrate-Nitrogen Concentrations 0.7 0.6 Current 766 l/sec +Proposed+ allocation Plausible limit from Nitrate-nitrogen concentratin (g/m 3 ) 0.5 Current FLAG 100% dryland Dairy Current+Proposed+ Plausible+Unlikely dairy 0.4 Double Current+ current Proposed irrigation 0.3 0.2 0.1 No development (AMA recharge zone) 0.0 0 500 1,000 1,500 2,000 2,500 3,000 3,500 Irrigated area in AMA recharge zone (ha) Main Spring Fish Creek AMA aquifer

Modelling Assumptions & Uncertainties • Water in = water out (water balance) • Nitrate in = nitrate out (no attenuation) • Nitrate fully mixed with flow reaching Te Waikoropupū • Marble aquifer ‘plumbing’ water balance consistent with Stewart & Thomas (2008) • Dairy farm N-leaching rates from OVERSEER™ ver 6.1.2; rates for other land uses from literature