1 10 th April 2012Slide # 1 K.P. Manikandan, Mohammad A. Qurban, T.V. Joydas, M. Wafar and P.K. Krishnakumar

2 10 th April 2012Slide # 2 Introduction Desalination is being used in 150 countries around the world, providing some or all the daily water needs of an estimated 300 million people There are now 16,000 desalination plants worldwide Total production = 77.4 million cubic meters per day (m 3 /d) (24 th IDA Worldwide Desalting Plant Inventory, 2012)

3 10 th April 2012Slide # 3 Introduction Red Sea 14% Arabian Gulf 45% Mediterranean Sea 17%  76% from three Seas 76%

4 10 th April 2012Slide # 4 Production in Arabian Gulf  45% of the global capacity

5 10 th April 2012Slide # 5 Production in Red sea  14% of the global capacity

6 10 th April 2012Slide # 6 Most desalination plants draw/pump water from the coastal waters Coastal waters are the biologically productive zone This is the zone where most marine animals prefer to lay eggs As most marine larvae are passive swimmers (at the mercy of water currents) they are vulnerable to suction during the intake Every year there is a huge loss of billions of aquatic organisms, including fishes, fish larvae and eggs, crustaceans, shellfish, and many other forms of aquatic life from the coastal ecosystems. This huge loss will reflect on the declining fish landing and ultimately to the revenues generated by Fishery. Introduction

7 10 th April 2012Slide # 7 Definitions Impingement: Potential injuries or loss of marine organisms retained on the intake screens. (as per USEPA > 9.5mm) Entrainment: Loss of marine organisms which enter the desalination plant with the source Seawater (as per USEPA < 9.5mm) Entrapment: impacts associated with offshore intake structures connected to an on-shore intake screen and pump station via long conveyance pipeline – Trapped Adult fishes Fish and invertebrate larvae

8 10 th April 2012Slide # 8 Typical Larval Cycle One Female 100,000 larvae 100 juveniles 2 ADULTS 99.9 % 98%

9 10 th April 2012Slide # 9 An example from Florida Florida’s - Tampa Electric Company (TECO) Big Bend station, situated on Tampa Bay, at Apollo Beach. Annually, impingement resulted in the loss of 419,286 “age 1” equivalent fish, and 11,113 pounds of fishery yield Entrainment was far more lethal: 7.71 billion- age 1 equivalent fish were being decimated; 22.8 million pounds of lost fishery yield. Most heavily hit were bay anchovies Stone crabs, pink shrimp, sea trout, herring and black drum were also affected.

10 10 th April 2012Slide # 10 Region-wise losses

11 10 th April 2012Slide # 11 Loss due to Impingement & Entrainment in Arabian Gulf & Red Sea – Unknown ?

12 10 th April 2012Slide # 12 To identify the methodology for quantifying the loss of marine organisms due to entrainment and impingement To recommend mitigation measures by way of alternative modes of seawater intake Objectives

13 10 th April 2012Slide # 13 Assessment- Methodology What to sample? Limited to only large and late stage larvae (Fish & Crabs) Phytoplankton to be ignored  Short generation times  Overly Abundant (bloom) can be a problem in quantification Small Invertebrate Larvae & Fish Eggs ignored – Cannot be Enumerated

14 10 th April 2012Slide # 14 Assessment- Methodology Sampling Locations: From the Intake Screens (for Impingement) In front of the Intake and at Water Body Locations using 300-μ mesh Plankton net (for Entrainment) Two replicate tows were taken with a minimum target sample volume of 30 to 40 m 3 for each net on the bongo frame. Sampling Frequency: 12 to 18 Consecutive Months Weekly – i.e., minimum of 52 Samples 24-hr Sample Collection for Impingement Day/Night Samples for Entrainment. Four times per 24-hr period—once every six hours.

15 10 th April 2012Slide # 15 For Impingement Assessment - Adult & Juvenile Species trapped on the plant Screens are: Identified/Classified Counted and Weighed For Entrainment Assessment – Larval Species Collected on the 300-μ nets in front of the screens & in various areas of the Potential Impact Zone are: Identified to the lowest taxonomic classification possible (e.g., genus or family level) and Counted Data Sets to be collected: For Each sample day, Larval Counts & densities (No. per Unit Volume) at the Intake & in Water Body. Actual Intake flows are measured at the time of sample collection. Assessment- Methodology

16 10 th April 2012Slide # 16 Assessment- Methodology Once species are identified and enumerated – the population and community levels effects caused by the removal needs to be estimated Long term data not typically available Models have to be used to estimate the potential effects of larval removal Estimating the Larval mortality due to entrainment Calculate the volume of water entering the intake (V) Measure the concentration of larvae (no. per volume) that are entrained (N) (assume 100% mortality) Estimate Entrainment mortality = N x V

17 10 th April 2012Slide # 17 Assessment- Methodology Demographic Models Adult Equivalent Loss (AEL) Fecundity Hindcasting (FH) Habitat Production Foregone (HPF) Conditional Mortality Models Empirical Transport Model (ETM) Models – two categories Those that require life history data and those that do not

18 10 th April 2012Slide # 18 Assessment- Methodology Requirements for demographic models Fecundity Age at first maturity Longevity Survival data for eggs, larvae and other stages through adults Adult Equivalent Loss Uses entrainment mortality in conjunction with larval sizes ( proxies for age) and natural mortality rates and estimate the Adult Equivalent loss Fecundity Hindcasting Uses entrainment mortality and back calculates the number of adult females that were lost (assuming 1:1 sex ratio or any other from literature)

19 10 th April 2012Slide # 19 Assessment- Methodology

20 10 th April 2012Slide # 20 Estimation of Habitat Production Foregone or Area Production Foregone HPF = Proportional mortality (P M ) x Source water body (SWB) An example from Carlsbad Desalination study Assessment- Methodology Entrained SpeciesProportional mortality (P M ) Source water body (SWB) HPF = Proportional mortality (P M ) x Source water body (SWB) Gobies acres65.11 Blennies acres26.06 Hypsopops acres19.57 Average (37 acres) So, HPF = 37 acres for 304 Million gallons per day in Carlsburg

21 10 th April 2012Slide # acres of new bay habitat if restored to the system will reduce the impacts caused due to impingement and entrainment- assuming that new bay habitat was a comparable mixture of habitats to that in source water body Scale and context of HPF are very important Two fishes have estimated entrainment losses (PM) of 1% – Case 1: northern anchovy has estimated source water of 1,000 km 2, results in HPF =10 km 2 – meaningless in a context as no habitat dependency for anchovy spawning – Case 2: kelp bass occupying kelp habitat around intake of 1 km 2, results in HPF = 0.01 km 2 – could be of greater concern if kelp habitat limited in area of intakes Mitigation could be by way of creating a coastal habitat similar to that of source water body, which will provide measurable long term environmental benefits Assessment- Methodology

22 10 th April 2012Slide # 22 Mitigation measures Sand Filtration

23 10 th April 2012Slide # 23 Mitigation measures Wedge Screens

24 10 th April 2012Slide # 24 Mitigation measures Subsurface intakes Vertical beach well Radial intake well

25 10 th April 2012Slide # 25 Mitigation measures Slant wells

26 10 th April 2012Slide # 26 Mitigation measures Horizontally directed drains (HDD) wells

27 10 th April 2012Slide # 27 Mitigation measures Marine Life Exclusion System

28 10 th April 2012Slide # 28 Conclusion The current US EPA standard requires that the best available technology should be used in order to achieve impingement reduction of 85-95% and entrainment reduction of 60-90% Middle east has the maximum number of desalination plants, but unfortunately, no estimate of loss due to entrainment and impingement in the Middle east There is an immediate need to assess the impacts of entrainment and impingement in the Middle east Only by quantifying the impact, measures could be taken to minimize the loss

29 10 th April 2012Slide # 29 Thank You