Appendix 6G Kings River Pilot Study Area (Forestry)
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APPENDIX 6G KINGS RIVER PILOT STUDY AREA (FORESTRY) For inspection purposes only. Consent of copyright owner required for any other use. EPA Export 24-03-2015:23:11:22 Three Rivers Project Final Report 1 KINGS PILOT STUDY AREA (FORESTRY) 1.1 INTRODUCTION Forestry in Ireland now comprises of approximately 649,813 hectares or 9% of the total land area. This percentage of forested land is one of the lowest in Europe. Much of this land is state owned and planted in the ‘50’s however, there has been a considerable increase in afforestion from the private sector since 1989 (Figure 1) Private forestry comprised of 253,088 hectares for 2000. Total new planting for 2000 was 15,695 hectares (13,669ha of conifers and 2,026ha of hardwoods). The private sector planted 14,231ha and the state planted 1,464ha. The Kings River catchment was chosen as a Study Area (SA) because of the overall significance of forestry in the upper Liffey catchments and the limited information available on the effects of commercial forestry activities on a river system. Figure 1: Growth in Forestry Ireland The basic objectives of the study comprised: 1. To define the nutrient export load generated in an active forestry catchment. 2. To examine the effects of commercial forestry operations on water quality. 3. To examine compliance with Forestry and Fisheries Guidelines (Code of Good Practice). The project worked in close co-operation with Coillte in the operational activities that were taking place in the catchment and with the EPA in choosing suitable hydrometric monitoring sites to compliment the water quality sites. For inspection purposes only. Consent of copyright owner required for any other use. 1.2 DESCRIPTION OF THE CATCHMENT AND PROJECT STUDY AREA The Kings River drains a catchment of 85km2 to the southeast of Pollaphuca Reservoir, into which it flows. The catchment boundaries include Moanbane and Mullaghcleevaun to the north, Turlough Hill to the east, and Table Mountain to the south. Catchment elevation varies from 823m at Mullaghcleevaun, down to approximately 150m at Pollaphuca Reservoir. The river system includes numerous tributaries, ranging in size from rivers to streams and brooks, and a multitude of minor streams that can vary from those carrying water all year round, to those appearing only during rainfall. During heavy rainfall, every available track, road, and drain turns into a gushing stream in an extremely short period of time typifying the flashy nature of the catchment. A project area of 5,496 hectares was selected from the overall Kings River catchment, extending from the upper catchment boundaries down to an area known locally as Knocknadroose, some 5km south- east of where the Kings River enters Pollaphuca Reservoir. This project area contains some of the more significant tributaries such as Ballinagee River, Annalecka Brook, and Ashbawn/Gleenreemore Brook, but excludes the Douglas River. A significant proportion of the landuse in the project area is commercial forestry, with large expanses of mountain moorland, an area of the Wicklow National Park, and a small degree of agriculture (predominantly sheep-rearing). Upper reaches of mountainside tend to be moorland, with forestry further down the slopes. Coillte owns approximately 1,570ha of the catchment (28% of the SA or 18% of the Kings River catchment), and dedicated agricultural land is likely to amount to less than 5% of the MCOS/192/001/002/Rp0036 1 Rev F01 EPA Export 24-03-2015:23:11:22 Three Rivers Project Final Report catchment. There are also areas of private forestry (mainly commercial partnerships with Coillte). The mountain moorland, although not dedicated farmland, is managed on a ‘commonage’ basis but has seen none of the degradation of vegetation and subsequent erosion of soil that was experienced in a number of the western counties. 1.3 FORESTRY ACTIVITIES This area was chosen as an SA due to the amount of commercial forestry and the subsequent forestry operations that would be carried out as part of an ‘active’ forest region. There are four main operations that take place; clear felling, re-stocking, thinning, and drainage. The impact of these operations on a river system can vary depending on the specific operation, the time of year that they are carried out (amount of rainfall), the topography of the area and the actual methodology employed during the operation. Blocks of forestry are sub-divided into areas known as SPs (sales proposals) and it is in these areas that the timber is sold and in which the four operations occur. 1.3.1 Clear Felling Clearfells can visually be the most disruptive operation occurring in a commercial forest area. Removal of timber, exposure of soils and tracking from clearfell machinery can all contribute to erosion of these fragile soils. The area of clear felling that took place during the lifetime of the project (October ’ 99 to September ’01) was approximately 106 hectares. All the timber was removed by conventional methods, which involved the use of specialised harvesting and gathering machinery referred to as a ‘Forwarder’ and ‘Processor’. This method of harvesting timber under suitable ground and weather conditions would seem to have little or no effect on soil disturbance and therefore little impact on local water quality. Another method that is sometimes used when weather and ground conditions are unfavourable for conventional machinery is referred to as ‘Skylining’. This method involves the use of manual labour to chainsaw the timber, which is then extracted using suspended steel cables. Skylining can also be used for extracting timber during ‘Thinning’ operations. This method of timber extraction for both clearfells and thinnings incurs greater costs, therefore, lower margins, and subsequently is only used when conventional machinery is unable to operate. For inspection purposes only. Consent of copyright owner required for any other use. MCOS/192/001/002/Rp0036 2 Rev F01 EPA Export 24-03-2015:23:11:22 LiffeyLiffey CatchmentCatchment For inspection purposes only. Consent of copyright owner required for any other use. Figure 2 Kings Pilot Study Catchment - Location Map EPA Export 24-03-2015:23:11:22 Three Rivers Project Final Report 1.3.2 Thinning This is an operation carried out to remove specific trees from a plantation to improve the final crop. The operation may take place a number of times in a particular block depending on the growth potential and the ease in which the site can be accessed. The area of timber that was thinned during the project was 366 hectares of which 38 hectares was thinned using the ‘Skylining‘ method. Generally this operation is less intrusive than the wholesale removal experienced during clearfelling. 1.3.3 Drainage and Re-Stocking Both of these operations occur post harvest generally sometime in the proceeding 12 months. Of the two operations, drainage would have to be considered the most likely to have a negative impact on the local river system. The “Code of Best Forest Practice – Ireland” issued by the Forest Service in the Department of the Marine and Natural Resources lays down guidelines for all the relevant operations including drainage. It has been found by the project these guidelines have been closely followed and adhered to in this catchment, thereby minimising operational impacts on surface waters. 1.4 MONITORING Four key areas were identified that required monitoring in the Kings SA: • Physico-chemical water quality • Biological Q-ratings • Hydrometrics • Monitoring of the various forestry activities, including compliance with Forestry and Fisheries Guidelines (Code of Good Practice). For inspection purposes only. Consent of copyright owner required for any other use. 1.4.1 Water Quality Monitoring – Physico-Chemical An approach was adopted to monitor WQ at each significant stream system, both upstream of forestry activities, and near the downstream end of the stream system. This means that several SP’s may be incorporated in the catchment between the two monitoring points. In some cases, all SP’s in a stream system may be of one type, e.g. harvesting, or SP’s may be mixed, e.g. harvesting and thinning. Given the number of SP’s expected for the duration of the project it was not possible to monitor each individually. In any case, the aim of the project was not necessarily to monitor specific forestry activities but rather the overall effect on the river. The original Kings system WQ monitoring networks comprised of sixteen water quality sites, one downstream site with autosampler (AS), and one temporary site. The initial water-monitoring network was reviewed and revised after approximately seven months for a number of reasons: • Results from the autosampler showed that there was a rise to peak flow in six hours and grab sampling occurred every seven days therefore the viability of grab sampling and its ability to yield representative data was questioned. • Therefore the investigation of specific sections of the Kings system in regard to water quality and nutrient loads export was not considered accurate by means of a grab sampling programme. The system was revised to monitor overall water quality in the area, with loads generated at the autosampler at the downstream end of the system MCOS/192/001/002/Rp0036 4 Rev F01 EPA Export 24-03-2015:23:11:22 Three Rivers Project Final Report The final water quality network comprised of eight grab sample sites and one autosampler (AS) site. These sites covered the majority of the major tributaries and were downstream of forestry blocks that contained the largest number of active SPs (Figure 3). Table 1 – Water Quality Sites Monitored August 2001 Combined Code River Name Station Name WQ Monitor RS9A01200 Annalecka us Kings River confluence Weekly RS9A0150 Annalecka 1.8km us Annalecka Weekly RS9K0130 Glashaboy Brook 200 us Annalecka Brook Weekly RS9G03100 Kings Liffey Ford 700 m us Kings Weekly RS9G05100 Kings Liffey u/s forestry at confluence Weekly RS9G06300 Kings Liffey Br us Kings confluence.