Heavily modified water bodies in Finland. Antton Keto and Kimmo Aronsuu Third Nordic workshop september 2010

Transcription

1 Heavily modified water bodies in Finland Antton Keto and Kimmo Aronsuu Third Nordic workshop september 2010

2 Introduction - defining hydromorphological status Hydromorphological status is evaluated with so called HyMocriteria In this method water bodies are given points according to the level of anthropogenic changes in their hydrological and morphological pattern Water bodies can be classified as heavily modified either according to the direct criteria or with the more specific evaluation with the HyMo-criteria

3 Direct criteria for classification as heavily modified water bodys Regulated lakes Water-level draw down during winter is over 3 m, or at least half of the average depth or decreases the water covered area to at least half of the regular size Rivers River has been changed by damming, cleaning, embanking or moving for at least half of its length or at least half of its natural head loss is dammed Dammed coastal bays No natural connection to the sea exists

4 Defining hydromorphological status in rivers with HyMo-criteria Criteria for hydro-morphological changes: Upstream migration barriers (% of river length) Constructed head loss (%) Constructed part (%) of the river length (cleaning, embankments, new channels, dry stretches) The daily discharge variation compared with mean discharge (HQwk- NQwk)/MQ under normal water conditions Change (%) in the spring HQ compared with the natural discharge or the occurrence of the critical low flows

5 Criteria for evaluation of hydromorphological changes in rivers (HyMo) 1. Upstream migration barriers 2. Constructe d head loss (%) 3. Constructed part (%) of river length (cleaning, embanking, new channels, dry stretches) and its effects 4. The magnitude of short-time regulation (1 (HQwk- NQwk)/MQ under normal water conditions or frequency of 0- discharge 5. Change (%) in the spring HQ compared with the natural discharge Very high (4 points) Completely closed (3 ( %) Over 50 over 50, This has caused destruction/significant negative changes in natural underwater habitats (e.g. rapids) Case-specific evaluation (2 Over 75 High (3 points) % closed > Natural underwater habitats largely destroyed / significantly changed Case-specific evaluation (2 > Moderate (2 points) % closed > At maximum third of natural habitats destroyed/ significantly changed Case-specific evaluation (2 >25-50 Slight (1 point) % closed Minor negative changes in natural habitats Case-specific evaluation ( No change (0 points) Less than 10 % Less than 5 Less than 5 Natural habitats Case-specific evaluation (2 Less than 10 1) Short-time regulation contains weekly and annual regulation. HQ-NQ can be calculated from a weeks period. 2) The effects on the water levels on down stream water courses shall be taken into account. 3) Excluding the short period possibilities to upstream migration. Can be evaluated in several discharge situations if necessary.

6 Defining hydromorphological status in lakes with HyMo-criteria Average winter draw down (m) or average winter draw down compared with the average depth (%) or change in water covered area (%) Raising or decreasing the mean water level (m) The proportion of constructed shore line of the lakes shore line (%) The effects of bridges and embankments Migration barriers

7 Criteria for evaluation of hydromorphological changes in lakes (HyMo) 1. Average winter draw down 1) (m) 2. Average winter draw down compared with the average depth (%) or change in water covered area (%) 2) 3. Raising or decreasing meanf water level (m) Average depth <1,2 m >1,2 m 4. The proportion of constructed shore line of the lakes shore line(%) 5. The effects of bridges and embankments 6. Migration barriers 3) Very high (4 points) > 3,0 >50 >1 >1,5 >50 Case-specific evaluation Migration of fish completely prevented High (3 points) >1,5-3 >30-50 >0,5-1 >1-1,5 >20-50 Case-specific evaluation Migration of fish almost completely prevented Moderate (2 points) >1,0-1,5 > ,1 0,5 0, Case-specific evaluation Migration of fish partly prevented or only some species are able to migrate Slight (1 point) 0,5-1, < 0,1 < 0,5 <10 Case-specific evaluation Only migration of some species is prevented No change (0 points) < 0,5 <1 0 0 <5 Case-specific evaluation All fish and the rest of aquatic fauna can migrate 1) The water depth at the time of the ice cover formation - the lowest water level during the period of ice cover. Calculate average e.g. from years ) Both factors shall be estimated. Points shall however be given for only one of the factors. 3) Can be evaluated in several discharge situations if necessary. Also the impacts of the migration barrier on the fish stocks can be taken into account.

8 Evaluation of hydromorphological status total score Level of hydromorphological change Changes in the hydro-morphological status HyMo-points 0 No change Slight change Quite significant change Significant change Very significant change 0-1 p. 2-3 p Excellent status HyMo-points 4-5 p. 6-9 p. 10- p. Moderate or worse status Heavily modified

9 Impact of migration barriers Dammed height related to total slopp Dredning, embankments, new channels Intensveness of short-term regulation Changes in spring discharge Total Should sesignate as HMWB Should not designate Designated as HMWB Did not designate Designation of Heavily Modified Rivers in NOREC Point estimates Opinions in the working group NOREC "decision" River Kalajoen keski- ja yläosa x Kalajanjoki x Siikajoen keskiosa x Pyhäjoen yläosa x Oulujoki x Iijoen alaosa x Pattijoki_Haapajoki x Kuonanjoki x Malisjoki x Luohuanjoki x Raate-Soilun-Kurki-Kynsijoki x Liminkajoki x Liminkaoja x

10 Opinions on the designation Working groups + Possibility to participate and understand the basics of decisions - The stakeholders usually knew well only 1 or 2 water bodies - Knowledge on ecological responses is limited - Lot of debate over scores Scoring system (and the reasoning of ordinance ) + Same, understandable basics for all environmental centres + Guidelines to estimate when hydro-morphological changes may prevent achieving good ecological status - The designation may be only calculating scores and percents without thinking ecology of the water bodies - Points of different factors are not comparable - The sum of the factor scores does not reflect the total ecological effect in all cases - National guidelines changed many times

11 Heavily Modified Water Bodies in Finland Until now, we have 6165 water bodies of which ecological status was possible to classify in 2600 water bodies Rivers 1604, Lakes 4286 and Coastal waters 275 There are altogether 126 heavily modified water bodies Lakes 32 Rivers 79 Coastal waters 13 There are altogether 29 artificial water bodies Lakes 25 Rivers 4 The number of heavily modified and artificial water bodies is 5 % of the total number of classified water bodies and 2 % of total number of all water bodies

12 Location of artificial and heavily modified water bodies Artificial Lakes Porttipahta and Lokk Lake Kemijärvi River Oulujoki Lake Kiantajärvi and Vuokkijärvi Lake Ontojärvi

13 Assessing The Status of HMWB

14 The connection between the positive ecological impacts of HyMo-measures and the status of HMWBs E C O L O G I C A L S T A T U S Current status Group 1. Slight improvement => HMWB meets Good Potential Current status Group 2. Moderate improvement => s tatus unclear Current status Group 3. Significant improvement => HMWB does not meet Good Potential Maximum potential Good Potential = T arget s tatus Improvement achieved by HyMo-meas ures Current s tatus

15 Assessing The Status of HMWB In NOREC The stakeholder working group took part also in classification The workshop was carried out in three regional sub-groups 1. Lists of all possible mitigation measures were prepared beforehand for every designated water body Also different levels of the same measure Background material on water bodies and costs of measures 2. Every member of the sub-group estimated which measures cause significant adverse effect 3. They estimated the impact of each measure on all biological quality elements (fish, bottom fauna, macrophytes, and water quality)

16 Assessing The Status of HMWB In NOREC 4. They selected a combination of measures, which had the highest possible ecological impact, but did not have significant adverse effect on specific use ( MEP-measures ) 5. Finally they estimated the ecological impact of MEP-measures on every quality element and an average on each quality element: 1) Slight improving effects (< 10%) => GEP 2) Moderate improving effects (10-40 %) => unclear 3) Significant improving effects (> 40%) => less than GEP Especially in the sub-groups, where both nature conservation organizations and power companies were represented, opinions on significant adverse effect and the impact of measures on ecological status varied.

17 Measure to improve the status of the River Kalajoki Fishways to HPPs. Discharge 0,5 m 3 /s. Used for 5 month/year. Fishways to HPPs, Discharge 0,5 m3/s. Used for 3 month/year. By-pass channels to the HPPs. Discharge of 1 m 3 /s trough the year. Stopping the short time regulation completely. Stopping the short-time regulation during June- August. Does the measure cause significant adverse effects on specific use? Yes No Fish Estimation of the effects of the measure on the biological quality elements and water quality( "1">40%,"2" 20-40%,"3" 5-20%,"4"1-5%, "5"<1%) Botto m fauna Macr o- phyte s Wat er quali ty Does the measure belong to the combination of measures in phase 3 x x x x x 4 4 x

18 Chosen measure: Fishways to HPP, discharge 0,5 m3/s, used 5 months in a year Estimation of the effects of measure combination to the biological quality elements and water quality on the following scale ( "1">40%,"2" 20-40%,"3" 5-20%,"4"1-5%, "5"<1%) Fish Bottom fauna Macrophytes Water quality RESULT GROUP 1: The chosen combination of measures has only slight improving effects on the ecological status. The HMWB meets good ecological potential (HyMo-test). x GROUP 2: The chosen combination of measures has moderate improving effects on the ecological status. It is unclear whether the HMWB meets Good Ecological Potential or not (HyMo test). GROUP 3: The chosen combination of measures has significant improving effects on the ecological status. The HMWB does not meet good ecological potential (HyMo test).

19 Assessing The Status of HMWB After the workshop national guidelines changed New task (6) was introduced: Estimate the restoration coefficient for MEP-measures : Significant (0.6) to very low (1.0) impact on ecological state Use the water quality classification to get a water quality class ( ) Multiply the water quality class with the restoration coefficient to get an estimation (0-1) of the state of HMWB Do the expert judgment of the status of the water body

20 Assessing The Status of HMWB Migratory fish paragraph was also introduced in the latest draft of the national guidance: In the GEP the ecological continuum is required in the rivers which have the potential to produce migratory fish stocks having high national or regional importance The final assessment of the status of each HMWB was carried out in the expert group of the environment center Opinions of the stakeholders presented in the earlier work shop were taken into account Also a new task (6) was performed The impact of measures on life cycle of migratory fish were emphasized The classification was presented in the working group and minor changes were done before closing the case for six years

21

22 Middle and upper part of the River Kalajoki