FURTHER INFORMATION REQUESTED BY THE COMMISSIONERS ON BEHALF OF DAVID DIPROSE IN THE MATTER

Transcription

1 FURTHER INFORMATION REQUESTED BY THE COMMISSIONERS ON BEHALF OF DAVID DIPROSE IN THE MATTER Proposed Southland Water and Land Plan BY DAVID DIPROSE Submitter EVIDENCE OF TERENCE LEONARD BROAD

2 2 SCOPE OF EVIDENCE 1. In my evidence I will present amended graphs as requested, respond to the statement "the limits presented on the graphs are irrelevant" made by the Chairman during his request, and include an analysis of the Proposed Southland Water and Land Plan Appendix E - Water Quality Standards. Mr Diprose uses this analysis to select the set of environmental factors for which to assess the impact his farms have on the environment. RESPONSE TO THE STATEMENT "THE LIMITS PRESENTED ON THE GRAPHS ARE IRRELEVANT 2. It is my thesis that the Limits Mr Diproses uses are relevant and similar Limits should be rolled out across the entire Region. That was the basic message of the submission; that best practice methods alone will not result in the restoration and maintenance of good water quality in Southlands rivers, lakes, and streams. 3. To achieve this goal, farmers require a simple straight forward set of standards. Limits for receiving waters with a degree of flexibility to cover flood events, small construction works, and unusual circumstances. Fresholds for point source or drain discharges which allow for mixing and assimilation, but with a lesser degree of flexibility on account of their higher concentration. 4. The following section is an analysis of the Water Quality Management Unit Standards associated with Ermedale Farm. WATER PLAN RECEIVING WATER STANDARDS 5. The Southland Region was divided into a number of Water Quality Management Units. Ermedale Farm lay across three units: Lowland Soft Bed, Lowland Hard Bed, and Spring Fed. Each unit had a set of environmental standards, which were objectives for streams within that unit (Table 1).

3 3 Variable Lowland Soft Bottom Lowland Hard Bottom Temperature 23 C 23 C 21 C ph Spring Fed Dissolved Oxygen 80% of saturation 80% of saturation 99% of saturation Clarity (Flow < median) 1.3 m black disk 1.6 m black disk >3.0 m black disk Total Ammonium (ph 6.5-7) (ph 6.5-7) < 0.32 Escherichia coli 1000 cfu/100ml 1000 cfu/100ml 1000 cfu/100ml Chlorophyll a < 50 mg/m 2 Algae Filamentous Diatoms and Cyanobacteria Summer <2 cm, <30%, <35g/m 2, Chl-a <120 mg/m 2 Summer <0.3 cm, <60%, <35g/m 2, Chl-a <200 mg/m 2 Chl-a mean 15 mg/m 2 Chl-a mean 15 mg/m 2 Bacterial & Fungal Slime No plumose or mats No plumose or mats No plumose or mats MCI >80 >90 >90 SQMCI >3.5 >4.5 >4.5 Fish Safe to eat Safe to eat Safe to eat Table 1: Water Quality Management Unit Environmental Standards. ASSESSMENT OF WATER QUALITY MANAGEMENT UNIT STANDARDS 6. The water quality variables outlined in the above section have their origins in Environment Southland State of the Environment Monitoring. One of the objectives of this investigation was to determine if Ermedale Farm was adversely effecting its rivers and streams and to what degree. To achieve this, variables that relate to potential discharges from Ermedale Farm must be chosen and monitored. These variables are not just relevant to Mr Diprose, but also every other farm of all types in Southland. TEMPERATURE 7. All Ermedale Farm waterways have been fenced and riparian zones of mature bush, scrub, tussock, and rank grass riparian zones were present. No discharges of hot water occur on Ermedale Farm. Consequently, water temperature in Diprose Dairy Farm streams and

4 4 drains are likely to be the result of natural environmental variation or upstream activities. Therefore, temperature would not be a suitable assessment variable. ph 8. Stream geology, in-stream processes, water quality from up stream, and ph of any discharges from Ermedale Farm will all combine to form the ph in Ermedale Farm streams and drains. Although measuring the ph can be done simply and cheeply it is the result of many factors. Therefore, ph would not be a suitable assessment variable. DISSOLVED OXYGEN 9. Abundance and growth of macrophytes, discharges of organic material and nutrients, and water turbulence are among factors that determine dissolved oxygen levels. Sunlight, nutrients, and streambed structure determines the abundance and growth of macrophytes. Sunlight is a highly variable factor influenced by stream aspect, geology, riparian zone structure, water clarity and season. Consequently, dissolved oxygen can be effected by many factors unrelated to potential discharges from Ermedale Farm. Therefore, dissolved oxygen would not be a suitable assessment variable. CLARITY 10. Poor clarity is indicative of higher levels of suspended solids which adversely affect the gills of fish and invertebrates, smother macrophytes, fill interstices in coarse stream beds, reduce visual distances for visual feeders and prey, and reduce dissolved oxygen. During times of normal flow when no bank or bed erosion, or run-off from land is occurring, water clarity is commonly very good. Normal flow is often defined as when a stream flow is at or below the median flow for that stream. When no flow data is available for a particular stream a reference site in a nearby stream is often used. During times of normal flow, water clarity can be reduced markedly through discharges from: open, piped and tile drains; bank and bed erosion through livestock access; and runoff from dairy shed waste, ploughed paddocks and winter-feed areas.

5 5 11. Appendix E Standards provide clarity measurements using black disk methods. This and other similar methods often require entry into streams or drains which is a totally unsafe practice in many locations. Also they are reliant on observers having no sight impairment. Given that around 10% of males are colour blind and another 10% may have minor colour difficulties, and perhaps 50% have known or unknown short or long sight deficiencies, these methods are fraught with operator variability. Also, with the naked eye, an average person can begin to see turbidity levels starting at around 5 NTU and greater (Myre & Shaw, 2006). The use of turbidity metres is becoming the accepted method because it does not require entry into streams, only a very small sample is required, and it has high precision. A formula is available (Dakota County, nd) to convert clarity distances into turbidity NTU units. Therefore, using a high quality turbidity meter to measure turbidity would be an effective assessment method. 12. When the clarity black disk distance measurements were converted into Turbidity NTU using the formula, NTU = (distance mm / ) (1/-0.662), the standards ranged from 1.5 NTU for Spring Fed to 5.4 NTU for Lowland Soft and Hard Bottom. These were consistent with the Otago Regional Council and Davies-Colley (2000) levels of 5 and 5.58 NTU respectively for lowland streams. 1.5 NTU and 5.4 NTU limit lines are appended to the Turbidity Graphs. TOTAL AMMONIUM 13. Total ammonium is also known as Ammoniacal-N, and in this submission unless otherwise stated is referred to as Ammonium. Potential sources of ammonium observed in streams can include dairy shed waste, livestock dung and urine, silage leachate, runoff and overspray of ammonium based and urea fertiliser, septic tank discharge, and sewage plant discharge. Without good management, all farms can discharge ammonium into waterways. Unaffected waterways would normally have concentrations close to NH + 4 -N. Ammonium is a plant nutrient and is also converted to the plant nutrients nitrite and then nitrate by bacteria. This process requires oxygen. Therefore, elevated ammonium concentration can influence macrophyte abundance, and dissolved oxygen concentration. Consequently, determination of ammonium concentration would be an effective assessment method. 14. Environment Southland ammonium standards refer to NH 4 +, not NH 4 + -N that is normally used for environmental monitoring. The nitrogen component of ammonium is what should be

6 6 determined and reported. Therefore, the Environment Southland ammonium standards were multiplied by , which is the conversion factor. This resulted in Standards of 0.19 and 0.25 NH 4 + -N. Both these levels are appended onto the ammonium graphs. 15. It should be noted however, these levels are very high and from the authors experience are rarely seen except in highly contaminated waters. In 2013 the EPA reviewed its limits and set the long-term chronic limit at NH + 4 -N at a ph of 7 and 20 C (USEPA, 2013). This was in response to fish health. But ammonium is part of the nitrogen group which are plant nutrients and when in elevated concentrations and with some phosphorous results in uncontrolled algae and macrophyte growth. The ORC recognised this and applied a limit of 0.1 for South Otago lowland rivers. ESCHERICHIA COLI 16. Escherichia coli (E. coli) are a bacteria and used as an indicator of faecal contamination. They are susceptible to ultra violet light, and cold, i.e. they much prefer dark and warm environments. Therefore, higher concentrations of E. coli in rivers are usually the result of direct discharge from sewage plants, rain assisted surface run-off of animal faeces from paddocks, and through mole or tile drains, or runoff from irrigated dairy shed wastewater. E. coli contamination can also come from septic tank discharges or leaks from urban sewage systems. Therefore, determination of E. coli levels would be an effective assessment method. 17. Environment Southland E. coli Standard was 1000 NTU. This level has been appended onto E. coli graphs. 18. However, this level is very high and well above that recommended for contact recreation, 260 cfu/100 ml (MfE, 2003). The ORC recognised this and applied a limit of 260 cfu/100 ml for South Otago lowland rivers. 19. Although low or no E. coli concentration is an important factor for water contact activities, the main purpose is to provide strong evidence of faecal contamination from stock, dairy shed waste systems, sewage waste systems etc. However, E. coli can also find its way into the water catchment via bird faeces (Don & Donavan, 2002). Also, recent research has found that E. coli populations can live and perhaps reproduce in soils, river and stream gravels and

7 7 sands, lake beach sands and also play an important role converting nitrite to ammonia in the nitrogen cycle (Byappanahalli et al, 2003; Byappanahalli et al, 2011; McLellan & Salmore, 2003; Osborne & Planer, 2013). To isolate these extraneous sources, urea should also be tested for. Together, elevated levels of E. coli, and detectable levels of urea are strong evidence, but not conclusive evidence, of contamination from stock waste. MACROPHYTES, BACTERIA AND FUNGI, AND CHLOROPHYLL-A 20. Abundance, growth and weight of macrophytes, bacterial and fungal slimes, and chlorophylla are effected by stream bed type, flow, sunlight, water clarity, depth of water, and nutrient composition and concentration. discharge, while others are not. Some of these variables may be the result of farm Measurement is also difficult and requires entry into streams. Therefore, abundance and growth of macrophytes, bacterial and fungal slimes, or chlorophyll-a, would not be suitable assessment variables. MACRO-INVERTEBRATE ANALYSIS 21. Streambed type, flow, macrophyte abundance and diversity, bacteria and fungal film abundance and diversity, sunlight, water clarity and suspended solids, and oxygen saturation influence the abundance and diversity of macro-invertebrates. Of these variables, only clarity could be related directly to a farm discharge. Many of the others are the primary result of nutrient discharge another factor directly related to a farm discharge. The process of carrying out a macro-invertebrate analysis requires entry into a stream and is very time consuming. Therefore, a macro-invertebrate analysis would not be a suitable assessment variable. FISH 22. It would be unlikely for the properties of a discharge from a farm to adversely effect a fish in such a way that it would be rendered unsafe to eat. Also, being able to associate a contaminated fish with a particular farm or discharge would be difficult because fish such as trout and eels have large home ranges and migration patterns. Therefore, the degree that fish are safe to eat would not be a suitable assessment variable.

8 8 Nitrite, Nitrate, and Dissolved Reactive Phosphorous 23. Nitrite, nitrate, and dissolved reactive phosphorous (DRP) are absent from the Water Quality Management Unit Standards. All three are important plant nutrients. Nitrite and nitrate are part of the nitrogen group. Unlike ammonium, they are highly leachable and are normally combined and reported as nitrite nitrate nitrogen (NNN). Nitrite and nitrate are derived from the nitrification of ammonium and are associated with livestock wastes. Nitrate based fertilisers are another source of nitrate contamination in streams. Phosphorous readily attach to clay particles and in this state is not available for plant uptake. DRP is available to plants and is usually associated with livestock wastes, fertiliser runoff, and soil erosion. On their own, dissolved N and P do not necessarily result in abundant plant growth, but together, especially in ratios about 16N:1P, aquatic plant growth can be extreme resulting in highly degraded streams. Water Plan Discharge Limits 24. An important objective used to guide the structure of a farm assessment programme is that the minimum number of samples are collected which will give the greatest amount of information. Environment Southland does not provide a comprehensive list of discharge limits but focus on mixing zones. Definitive Discharge Limits set somewhat above Receiving Water Standards to allow for mixing would provide targets to aid farmer in their management without imposing multiple sampling across the end of a mixing zone. The Environment Southland Water Plan provided a number of Discharge Rules pertinent to farming. Assessment of Discharge Limits Rule Discharges into water bodies that meet the (Receiving) Water Quality Standards do reduce the water quality below the (Receiving) Water Quality Standard after reasonable mixing.

9 9 Rule Discharges to surface water bodies that do not meet the (Receiving) Water Quality Standards - the effects of the discharge must be minor. Rule 10. Discharge of Fertiliser 27. No direct discharge into surface water and all practical measures against fertiliser drift. Regional Effluent Land Application Plan Sludges 28. The plan provides application rates and prohibits runoff from sludge to water. Regional Effluent Land Application Plan Environmental Monitoring sites around the region that are monitored on a monthly basis for: aquatic plant growth (Macrophytes and Periphyton), dissolved oxygen, ph, nutrient levels (e.g.: nitrates), waterborne pathogens (faecal coliforms), and water clarity. 30. The rules provide for mixing zones, which are fraught with measuring problems. Qualitative visual assessments are not acceptable for farm discharge assessments. Rule 1 allowed discharges to reduce water quality in a stream to the Receiving Water Standard. Rule 2 allowed further reductions in Receiving Water Quality when a stream already exceeded the Standard, but only at minor increments. Rule 10 stated that no direct discharge of fertiliser into water should occur, but, as long as a practical measure against drift had occurred the rule implied a discharge to water could occur. The Regional Effluent Land Application Plan prohibited the runoff of sludge and identified a number of variables Environment Southland monitored. These included ammonium, faecal coliforms, and clarity. As identified in Section 2.1.2, these variables were appropriate for assessing farm runoff but not their levels. 31. The Environment Southland Land and Water Plan provides no definitive Discharge Limits except to say that the discharge should (essentially) not reduce the water quality below the Receiving Water Quality Standard. However, mixing zones were provided for.

10 NTU In the absence of any discharge limits it is important to provide an alternative. The ORC provides definitive Limits for all assessment variables except turbidity for which a qualitative guide was provided. This is a failing of their effects based limit setting system. The limits are set somewhat above the Receiving Water Standard at a level that after mixing and assimilation the quality of the receiving water will not decline. 33. Gessford (2011) stated that up to a 15 NTU increase over natural levels is acceptable for aesthetics, fisheries, aquatic life, and water orientated wildlife. This should be adopted as the Assessment Limit for the turbidity level in discharges above that of the Receiving Water Standard. Amended Graphs Median Turbidity Level Error Bar: Median Absolute Deviation The lower limit shown on the graph is for Spring Fed Stream which Gorge Stream is not Gorge Stream Median NNN Level Error Bar: Median Absolute Deviation There is no NNN limit Pourakino River

11 11 Median Ammonium Level Error Bar: Median Absolute Deviation The upper limit is for Lowland Soft and Hard Bottom of which Pourakino is Pourakino River Median E. coli Level Error Bar: Median Absolute Deviation Pourakino River The high E.coli limit is the same for all three stream types, even Spring Fed, which being sourced from a spring should have very low or no E. coli. 5.0 Median NNN Level Error Bar: Median Absolute Deviation No NNN limit North Boundary Creek

12 Sum/Aut 2015 Sum/Aut Median Ammonium Level Error Bar: Median Absolute Deviations The upper limit is for Lowland Soft and Hard Bottom Streams which North Boundry Ck is one North Boundary Creek Median E. coli Level Error Bar: Median Absolute Deviations The high E.coli limit is the same for all three stream types. 0 North Boundary Creek NNN Error Bars: accuracy of the test values ± No NNN limit therefore all concentrations are acceptable. House Up House Down North Boundary Creek

13 NTU Sum/Aut 2015 Sum/Aut Ammonium Error Bars: accuracy of the test values ± The limit line is for Lowland Soft and Hard Bottom Stream which North Boundary Ck is House Up House Down one. North Boundary Creek Nitrate Level House House North Boundary Creek Nitrite Level House House North Boundary Creek Median Turbidity Level Error Bar: Median Absolute Deviations Median DRP Level Error Bar: Median Absolute Deviations Pond Inlet Pond Outlet Chip Filter Midstream Grays Flat Drain 0.00 Pond Inlet Pond Outlet Chip Filter Midstream Grays Flat Drain Median NNN Level Median Ammonium Level Median E. coli Level Error Bar: Median Absolute Deviations Error Bar: Median Absolute Deviations Error Bar: Median Absolute Deviations Pond Inlet Pond Outlet Chip Filter Midstream Grays Flat Drain 0.00 Pond Inlet Pond Outlet Chip Filter Midstream Grays Flat Drain 0 Pond Inlet Pond Outlet Chip Filter Midstream Opouriki Stream

14 14 References Byappanahalli, M., Fowler, M., Shively, D., and Whitman, R., 2003: Ubiquity and Persistence of Escherichia coli in a Midwestern Coastal Stream, Applied Environmental Microbiologl, Aug 2003, Vol 69, No 8, pp , American Society for Microbiology. Byappanahalli, M. N, Roll, B. M., Fujioka, R. S., 2011: Evidence for Occurance, Persistence, and Growth Potential of Escherichria coli and Enterococci in Hawaii s Soil Environments, Microbes Environ. Vol. 27, No. 2, , 2012 Dakota County, nd: Indicator: Water Clarity, Dakota County Soil and Water Conservation District, Dakota County, Minnesota, downloaded on 12/6/2017 from Don, G. L., and Donavan, W. F., 2002: First Order Estimation Of The Nutrient And Bacterial Input from Aquatic Birds To Twelve Rotorua Lakes, for Environment Bay of Plenty, Bioresearches, Auckland, New Zealand, October Gessford, S. K., 2011: Turbidity and Conductivity, Resources, Graduate Program of Teton Science Schools, Interdisciplinary Science Education, Montana State University, ads/pdf/tlc/streamteambackground/turbidity%20and%20conductivity.pdf downloaded 25 May. MfE, 2003: Microbiological Water Quality Guidelines For Marine And Freshwater Recreational Areas, Ministry for the Environment, Wellington, downloaded on 13/6/2017 from McLellan, S. L., and Salmore, A. K., 2003: Evidence For Localized Bacterial Loading As The Cause Of Chronic Beach Closings In A Freshwater Marina, Water Research 37 (2003) Myre, E. and Shaw, R., 2006: The Turbidity Tube: Simple and Accurate Measurement of Turbidity in the Field, Department of Civil and Environmental Engineering, Michigan Technological University, downloaded on 12/6/2017 from Osborne, J. P., and Planer, J., 2013: Nitrate (Anaerobic) Pathway Map, Compounds and Reactions, Manchester College, Indiana, USA, downloaded on 13/6/2017 from

15 15 USEPA, 2013: Aquatic Life Ambient Water Quality Criteria For Ammonia - Freshwater, U.S. Environmental Protection Agency Office of Water, Office of Science and Technology, Washington, DC, downloaded on 13/6/2017 from Name Terence Leonard Broad Title Ecologist Date June 2017