Especificaciones del equipo de fondo.

5.1.1 Dams and Impounding Reservoirs

As fully reported for the DBP, the number of Dams and Impounding Reservoirs is confirmed as 22 as identified in the corporate Aquarius system and reconciled with reports under the Reservoir Act and PR04 data. This is an increase of two from PR04. The Anglian Water Reservoir Safety Manager (a Supervising Engineer under the Reservoirs Act) has graded all the reservoirs as Grade 2, an improvement at one reservoir – Cadney Carrs from Grade 3 at PR04 to Grade 2 at PR09.

For FBP, a COPI value of 1.2656 has been applied to the AMP4 valuation. At DBP, it was confirmed that the original cost data was derived in 1993 and subsequently inflated for each AMP. When challenged, the Company stated that it would not be appropriate to derive costs by any other method for these long life assets as there had been little construction of this type of asset in the UK in recent years.

5.1.2 Raw Water Aqueducts

The Company has used the same approach to identify the asset stock, condition and value as for water mains and therefore included the approach in the section relating to mains. Raw water aqueducts are defined as assets which convey water from the ‘environment’ to ‘treatment i.e. pipes (borehole sources) and tunnels. The new methodology for Condition Grading issued by Ofwat has lead all aqueducts in the region to be classified as CG1 due to the ‘no failures’ scenario. At PR04 all assets were reported as CG3.

5.1.3 Water Mains

The Company’s approach was reviewed and described for the DBP, a procedure which has been maintained for the FBP. The Company applied the UKWIR Report No 08/RG/05/22 Volume 2 – Mains Condition Grading, the result of which is an overall improvement of condition grade.

Anglian Water believes that the original Ofwat methodology did not provide a good CG profile and, as a consequence, has used an improved water network modelling approach (SynerGEE) to provide a more reliable assessment. The entire region was covered and an assessment of ‘real’ running pressures which could affect the ‘cohort’ approach was applied to all pipes. This has been a proactive approach by

the Company on this assessment methodology following a similar approach that was in place prior to the Ofwat/UKWIR methodology.

As required, Anglian Water followed the cohort procedure and the Pareto curves as reproduced in the Reporter’s Commentary for the DBP and included in the Anglian Water FBP Company Commentary. SMC is satisfied that the Company has applied the methodology as intended by Ofwat and has described in detail the findings in the Company Commentary. To the extent we are able from our limited review we confirm that the GIS system (from GWaterUK) provides an appropriate basis on which to develop the cohorts.

Anglian Water identified 155km of mains outside the four specified Bands as these were mains without a size recorded and has proportionally distributed these mains into the four size Bands.

The Anglian Water total is reported as 37,232km in Table C3.1 (Lines 21 and 22) plus 100km Other Mains (Line 23). A total of 649km has been identified as Non- potable Water Mains, consisting of 549km of Raw Water Aqueducts and 100km of Other Mains (95.6km for the former Anglian Water region (ANG) and 5.5km for Hartlepool Water).

SMC is satisfied that the final cohort iteration for both size bands met the corrected criteria from the UKWIR report of 1.0 burst per year per cohort.

The results from this approach are detailed below and provide the base data for the new Table 3.1a.

Condition Grade Smaller Diameter Larger Diameter Total km % 1 19,453 2,229 21,682 58.24 2 11,095 69 11,164 29.98 3 3,807 28 3,835 10.30 4 485 7 492 1.32 5 57 1 58 0.16

Age bands were further developed and updated from the company’s foundation dataset of historical development polygons.

Anglian Water has clearly shown that the lengths of water main within the condition grades are different when considering the cohort approach to the Pareto curves. The advantages and disadvantages of the cohort approach are described in detail in the company commentary.

The Company has calculated the MEAV by assuming replacement would be 80% by directional drilling and 20% by open cut. As described in 4.2.1 above, the valuations recalculated using a larger selection of surface type. As a result, the GMEAV for all potable mains has risen from £3.6bn at PR04 (02/03 prices) to £4.2bn (07/08 prices) for PR09, an increase of 16.7%.

Anglian Water has reported a similar length of water mains to sewers (37,300km and 39,700km respectively), however the asset value of water mains is significantly less i.e. less than 25% of the wastewater value - see paragraph 5.2.1 below. Anglian Water, in its commentary, has confirmed the extensive use of trenchless

technology (directional drilling) as the preferred method for replacement and this could be the reasoning for this lower value.

There is a significant difference in valuation for the water main and sewerage asset stock, some of which can be attributed to location, depth and method of replacement. However, there is a clear need for the Reporter to be informed and understand the ‘national’ trend before further comment on this difference can be made.

Strategic mains are regarded as those with a ‘nominal’ diameter >320mm.

Other Mains are generally raw water supplies to industry mainly, the majority being the supplies to the Humberside refineries in North Lincolnshire. A similar approach to the condition grade determination for water mains has been applied.

Anglian Water considers that relatively few bursts occur on an annual basis since many mains were replaced rather than relined during AMP3 and the early years of AMP4.

5.1.4 Communication Pipes

Ancillaries – infra are generally customer communication pipes and an extensive exercise has been carried out to provide a unit cost for a standard length of pipe and stop cock box. Following lengthy discussions in previous PR review meetings, Anglian Water has concluded – and agreed with previous Reporters – that the valuation associated with ‘long’ and ‘short’ communication pipes balance out. A single average length of 7m has been used and cost variation is mainly due to material and labour costs rather than re-instatement due to the use of trenchless technology installation methods. For the DBP, we reported that the Company calculated an average communication pipe length of 8.3m which it compared to the Cost Base assessment of 7.7 m and determined the number of live communication pipes from their SAP billing system. Anglian Water subsequently confirmed the

average communication pipe length to be 7.7m for the FBP.

5.2

Sewerage Service

5.2.1 Sewers and rising mains

A review of the sewer length data provided in the company commentary and Table C3.3 identified some ‘irregularity’, the result of which was an amendment to the company commentary.

Critical sewers are identified by using GIS applications based on Sewer Rehabilitation Manual criteria and is based on location, size, material, type, traffic flows, property types, main river (only) etc. The audit discussion confirmed that some aspects of ‘traffic sensitivity’ have not been included to date due largely to the complexity of identifying and applying the criteria. Anglian Water considers its percentage of critical sewers to be mid-table as a Water and sewerage company. The analysis of the sewerage data supports this view, although an increase would occur if traffic sensitivity was applied in full. The document “AWS Sewer & Pumping Main Criticality for JR06” provides the criteria for identification and confirms that not all SRM criteria are fully applied yet. The results of the current assessment are summarised in the table below.

The length of critical sewer has increased significantly since PR04 (+47%), due largely to improved assessment methods, the application of a greater selection of

surface type (road, grass etc) and recognition of proximity to main rivers. The updated EA main river set information has impacted on this criticality rating and added more lengths of main river in the region. In addition, a good GIS set of railway data has been provided by Network Rail. The percentage of critical sewers was approximately 25%. The apparent ‘no change’ percentage at PR09 is due to the additional 4,800km of non-critical sewer to the asset stock, due mainly to improved former S24 data.

Anglian Water has an estimated 8,500km of former S.24 sewers of which 6,000km is unmapped i.e. only 30% of this type of asset stock is mapped. The mapped length of former S.24 sewers is included in the average sewer length calculation which has subsequently reduced to 34.5m as a result.

Compared to most water companies, Anglian Water has a high percentage of pumping and vacuum assets in its wastewater stock – 4,099km of a total of 43,767 is 9.4% of the asset stock.

There are no specific guidelines within the SRM to determine the criticality of pumping mains. Some companies apply the gravity sewer criteria which is not appropriate due to the size bands in particular and the effect of the failure of a relatively large sewage pumping main, say 225mm dia. If the gravity sewer criteria were used, the percentage on non-critical pumping mains would be well in excess of 90%. Anglian Water has made a determined approach to provide a more realistic length, as described in its criticality guidelines produced for JR06 the results of which are shown in the table below. For rising and vacuum mains each main was subdivided in 10m sections and each 10m length assessed for criticality based on location, diameter etc. This length was identified as the average width of a road and therefore a reasonable unit length for analysis purposes.

The analysis of the sewerage data has identified the following non-critical sewer and critical sewer relationship. The data in the table below is a summary of the data provided by Anglian Water in Table 5.2 and para 6.113 of the FBP company commentary. However, these numbers do not fully reconcile with the data provided in Table C3.3 Lines 1 to 3 which is due to the different JR and PR reporting requirements.

Sewer Type Total Length (km) Length Non- critical Sewers (km) Length Critical Sewers (km) Critical Sewers % Gravity Sewers 39,668 29,456 10,212 25.7 Rising Mains 4,099 2,712 1,387 33.8 Total 43,767 32,168 11,599 26.5

As described above sewers are classified by material, depth, dia., age, soil (SRM definitions) using a computerised approach. For PR04, the assessment of 100km CCTV survey was completed in each ‘class’ to identify a condition profile for each class. Anglian Water now has 1100km of CCTV data from DASs, proactive sewer rehabilitation studies and DG5 schemes which have been assessed to generate condition profiles. Anglian Water has not considered the condition grade over-ride approach, say for high water table or tidal reaches where the effect of infiltration and exfiltration is more marked. However, where poor soil conditions exist, such an approach is used. Surveys are assessed using ‘ICAM’ software which sits above

sewer.dat data and uses detailed coding to provide the defect density over the full length of sewer.

Much of the CCTV survey programme follows a proactive cluster approach in coastal and Essex areas due to the high number of collapses that occur in these regions. Consequently, it may be appropriate for Anglian Water to re-consider the over-ride approach when considering condition grading at least in ground which is subjected to tidal influences. SMC has suggested that the gravity sewer condition grading may be slightly underestimated since the opportunity to upgrade certain defects in sewers which may be affected by tidal conditions and/or a high water table has not been taken by the Company

The company commentary for the FBP implies that some Condition Grade 5 (CG5) defects can be ‘simply’ repaired by the installation of a CIPP patch repair. However, Anglian Water confirmed that such a repair would usually include re-rounding the sewer prior to applying the patch lining repair. Defective connections were also discussed in detail since many Sewerage Undertakers have a higher percentage of CG4 sewers which is the result of using a specific type of sewer assessment software. Anglian Water advised that the company uses the ‘EN’ scoring method consequently this did not become an issue.

As described in detail for the DBP, Anglian Water used the UKWIR methodology to calculate condition grade of the rising mains and vacuum systems for water mains. As reported in the FBP, the majority of the pipework, some 97%, was calculated to be in CG1 and considerably less pipework in CG4 and CG5 compared to the grades reported for PR04. Anglian Water reviewed the failure data which confirmed that the failure rate was approximately 30% of the water main failure rate. The UKWIR methodology cohort parameters were adjusted by 30% to reflect this position and revised CG data was produced which provided a more realistic set of CG data as shown in the table below. This approach has provided a more suitable CG grading profile and has proved realistic when compared to actual failure analysis. Anglian Water undertook a major pumping main repair and replacement exercise during 2005-06 which confirmed that the main areas of failure are 1970s PVC; 1950s AC and WW2 Iron products.

Data Set CG1 % CG2 % CG3 % CG4 % CG5 % PR04 16.4 11.7 54.4 6.6 10.8 PR09 (orig) 96.9 2.7 0.1 0.0 0.1 PR09 (rev) 59.5 32.1 6.5 1.8 0.1

At PR04 Anglian Water was funded for water main replacement and a similar approach is proposed by Anglian Water for wastewater pumping mains in AMP5. The identification of pressure mains as a proactive approach (i.e. replacement prior to failure) has been a difficult process to date. However, the WRc has developed new technology and assessment procedures to identify defective mains prior to failure – project reference CP371. If successful in its application, this would provide a proactive approach to avoid service failure and particularly important for Anglian Water’s high percentage of wastewater pressure mains.

The approach to the calculation of MEAV is similar to that for the water mains using Anglian Water cost curves. As described in 4.2.1 above, the valuations recalculated using a larger selection of surface type. The Company attributes the change in valuation to this change in methodology. As a result, the Gross MEAV has increased from £13.9bn at PR04 to £16.7bn for PR09, a rise of almost 20%.

As for water mains, the age profile for sewers has been derived from the inspection of historical maps plus general knowledge of pipe materials.

5.2.2 Sea Outfalls

There have been a number of changes between long and short sea outfalls resulting from the review of all sea outfalls using GIS as described in Table C3.3 Lines 18 and 19.

5.2.3 CSO and Emergency Overflows

Following the challenge by SMC at DBP regarding some of the assets identified as CSOs and EOs, Anglian Water has reviewed the data and provided a reduced number of 2,135 installations. The main reasons for the amendments were due to duplication of consents (to discharge) and better information. However, the number has increased by 160 overall from PR04 due to an error made at the previous review and the identification of some previously unconsented overflows.

Most CSOs reported are static screen installations but powered screens are reported and presumably valued with pumping stations (SPS) since the majority are at SPS locations.

Of the number reported, 588 are of known size bands based on consented flow rates: Band 1 = <200l/s; Band 2 = 200l/s to 500l/s; Band 3 = >500l/s flows. The majority of screens are in Band 1 due to the static screen influence. Apart from a general assumption that uniform deterioration at a rate of 4% from PR04, the approach to condition grading range remains unaltered from PR04. Consequently, the valuation has been based on the same principles as for PR04 but with revised unit costs. The CSOs, including the overflow pipe and end structure, have seen a large increase in value due to the increased number and to the average unit cost of £35,104. The unit cost is updated on a regular basis as new construction adds to the asset stock. However, if as stated in the company commentary, the CSO chamber is included in the gravity sewer valuation, there is a potential large proportion of CSO replacement cost which is omitted from the unit cost above. A new CSO chamber is designed to nationally accepted ‘WaPUG’ standards and cannot be regarded as a ‘manhole’, consequently this approach to CSO valuation should be reviewed. The Anglian Water approach to valuation based on new build costs was also challenged at DBP.

We requested the number of CSOs and EOs which are screened and of these how many are static or powered screens. Anglian Water has responded to the statement with the comment: -

“We do not record all static screens on our systems.

Powered screens are recorded on our SAP ALM system. The data structure of our SAP system records the screens on each site (e.g. inline pumping station, STWs), whether the screen is an inline screen, inlet screen or a storm screen and the screen type (e.g. drum. mechanically raked bar, static bar). We do not specifically record whether the screen is on an overflow.

For example: We have 159 screens recorded on non STW sites, 5 are inline screens, 76 are inlet screens and 78 storm screens. Of the 78 storm screens (which are most likely to be overflow screens) 32 are mechanically raked screens, 35 are static bar screens, 6 are rotary screens, 4 are ‘D’ screens and 1 is a drum screen.”

In addition SMC suggested that an improved database would provide Anglian Water with the opportunity to have a more accurate size band determination and

consideration of the introduction of a unit cost for each size band. Anglian Water responded to this statement with the comment: -

“While we agree that an improved database would improve the opportunity to have a more accurate size band determination, we believe that our current extrapolation of the sample of our known asset sizes (27% of total CSOs and EOs) provides a reasonable approach. Our confidence grade of B3 for the reported asset stock by size band reflects this extrapolation.”

We also suggested that Anglian Water should consider a review to its approach for CSO valuation to which Anglian Water responded with the comment: -

“We believe that our current approach to valuation of these assets is reasonable given that the total value accounts for less than 0.5% of the sewerage infrastructure GMEA.”

The details provided suggest that there is little or no inspection of CSOs and EOs. Since the majority of screened CSOs are static screens, these should be inspected at least every 3 months for maintenance purposes and possibly more frequently in some locations particularly if, for example, there is a specific grease problem.