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<h4>2018</h4>
Portsmouth Water has no large raw water storage reservoirs.  It relies almost entirely upon groundwater reserves in the chalk aquifers of the South Downs and abstracts its raw water from wells, boreholes and springs.  It has one river abstraction at Gaters Mill on the River Itchen, a chalk river with a groundwater baseflow.

Those reserves rise and fall with the seasons and so Portsmouth Water pays particular attention to the local hydrogeological data by monitoring rainfall at its Havant Offices, groundwater levels in the chalk at Idsworth on the Hampshire/Sussex border, as well as the total yield from the natural springs at Havant and Bedhampton.

These resources are monitored on a daily basis and reported upon on a monthly basis.  The information here is therefore at times one month behind the most current situation.

The information gathered is reproduced here for information purposes; no guarantee is given as to its accuracy.

<em>The information provided in this section shows the Water Supply data for the 12 months from April to March. The monthly data for our resource levels can be found <a href="https://www.portsmouthwater.co.uk/category/water-supply-news/">here</a>.
</em>

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[accordion title="" open1st="0" openAll="0" style=""]

[accordion_item title="Rainfall"]

The weather during 2017/18 was unusual with a dry October and November and a dry February. Over the year rainfall was 100% of the long term average and rainfall in December, January and March was sufficient to ensure full groundwater recharge.

The graph below shows recorded rainfall as a blue bar and the Long Term Average rainfall as a black line.<a href="https://www.portsmouthwater.co.uk/wp-content/uploads/2018/07/havrain2017-8-1.png"><img class="aligncenter wp-image-7163 size-full" src="https://www.portsmouthwater.co.uk/wp-content/uploads/2018/07/havrain2017-8-1.png" alt="" width="992" height="556" /></a>

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[/accordion_item]

[accordion_item title="Groundwater Levels"]

The Company has monitored the groundwater level at Idsworth Well, Rowlands Castle, for many years since the well is unaffected by abstraction and is representative of groundwater conditions in the South Downs chalk.  Around 85% of Portsmouth Water’s abstractions are from underground sources and so groundwater levels are critical to maintaining supplies.

Groundwater in the local aquifer normally fluctuates approximately 9.5m between maximum and minimum annual levels. Groundwater levels were below average at the start of 2017/18 and a dry April and June resulted in levels close to the drought trigger in July. Rainfall in July, August and September prevented a drought from developing. There was a strong recovery in groundwater levels after this due to a wet winter.

<a href="https://www.portsmouthwater.co.uk/wp-content/uploads/2018/07/ids.png"><img class="wp-image-7164 size-full aligncenter" src="https://www.portsmouthwater.co.uk/wp-content/uploads/2018/07/ids.png" alt="" width="860" height="580" /></a>

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[/accordion_item]

[accordion_item title="Abstraction"]

Annual abstraction is drawn from three types of source: the River Itchen Works which treats surface water, boreholes and wells which abstract groundwater from the underground chalk, and Farlington Water Treatment Works which treats spring water from Havant and Bedhampton.

Abstraction from the Company’s sources in 2017/18 was as shown in the table below:
<table width="531">
<tbody>
<tr>
<td rowspan="2" width="168">Source</td>
<td colspan="4" width="364">Annual Abstraction - Ml/Yr</td>
</tr>
<tr>
<td width="87">Source Licence</td>
<td width="101">Source Actual 2017/18</td>
<td width="87">Group Licence</td>
<td width="88">Group Actual 2016/17</td>
</tr>
<tr>
<td width="168">Northbrook</td>
<td width="87">7,487</td>
<td width="101">5,757</td>
<td rowspan="2" width="87">7,487</td>
<td rowspan="2" width="88">5,757</td>
</tr>
<tr>
<td width="168">Lower Upham</td>
<td width="87">640</td>
<td width="101">0</td>
</tr>
<tr>
<td width="168">West Street</td>
<td width="87">3,328</td>
<td width="101">1487</td>
<td width="87"></td>
<td width="88"></td>
</tr>
<tr>
<td width="168">West Meon</td>
<td width="87">166</td>
<td width="101">15</td>
<td width="87"></td>
<td width="88"></td>
</tr>
<tr>
<td width="168">River Itchen</td>
<td width="87">15,916</td>
<td width="101">8,455</td>
<td width="87"></td>
<td width="88"></td>
</tr>
<tr>
<td width="168">Maindell</td>
<td width="87">2,040</td>
<td width="101">56</td>
<td width="87"></td>
<td width="88"></td>
</tr>
<tr>
<td width="168">Soberton</td>
<td width="87">3,294</td>
<td width="101">1,741</td>
<td rowspan="2" width="87">3,294</td>
<td rowspan="2" width="88">1,742</td>
</tr>
<tr>
<td width="168">Newtown</td>
<td width="87">695</td>
<td width="101">1</td>
</tr>
<tr>
<td width="168">Worlds End</td>
<td width="87">8,296</td>
<td width="101">3,463</td>
<td width="87"></td>
<td width="88"></td>
</tr>
<tr>
<td width="168">Lovedean</td>
<td width="87">4,148</td>
<td width="101">2,179</td>
<td width="87"></td>
<td width="88"></td>
</tr>
<tr>
<td width="168">Havant &amp; Bedhampton</td>
<td width="87">35,770</td>
<td width="101">18,588</td>
<td width="87"></td>
<td width="88"></td>
</tr>
<tr>
<td width="168">Walderton</td>
<td width="87">9,955</td>
<td width="101">7,247</td>
<td rowspan="6" width="87">23,740</td>
<td rowspan="6" width="88">17,169</td>
</tr>
<tr>
<td width="168">Woodmancote</td>
<td width="87">1,103</td>
<td width="101">371</td>
</tr>
<tr>
<td width="168">Fishbourne</td>
<td width="87">3,741</td>
<td width="101">1,919</td>
</tr>
<tr>
<td width="168">Funtington</td>
<td width="87">2,920</td>
<td width="101">1,642</td>
</tr>
<tr>
<td width="168">Lavant</td>
<td rowspan="2" width="87">9,950</td>
<td width="101">4,415</td>
</tr>
<tr>
<td width="168">Brickkiln</td>
<td>1,575</td>
</tr>
<tr>
<td width="168">Eastergate</td>
<td rowspan="4" width="87">&nbsp;

&nbsp;

10358*

&nbsp;</td>
<td width="101">2,137</td>
<td rowspan="4" width="87">10,358</td>
<td rowspan="4" width="88">6,813</td>
</tr>
<tr>
<td width="168">Westergate</td>
<td width="101">2,072</td>
</tr>
<tr>
<td width="168">Slindon</td>
<td width="101">618</td>
</tr>
<tr>
<td width="168">Aldingbourne</td>
<td width="101">1,986</td>
</tr>
<tr>
<td width="168">Total</td>
<td width="87">116,066</td>
<td width="101">65,724</td>
<td width="87">44,879</td>
<td width="88">31,481</td>
</tr>
</tbody>
</table>
&nbsp;

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[accordion_item title="Treated Water Distributed"]

The dry weather in May produced an early peak in demand but the wet July suppressed the summer peak. There was an unusual peak in March due to the cold weather and a large number of burst mains. The situation was brought under control quickly and overall demand for the year was higher than normal but not unusual with an average demand of 174.4 Ml/d.

<a href="https://www.portsmouthwater.co.uk/wp-content/uploads/2018/07/distin.png"><img class="alignleft wp-image-7165 size-full" src="https://www.portsmouthwater.co.uk/wp-content/uploads/2018/07/distin.png" alt="" width="892" height="580" /></a>

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[/accordion_item]

[accordion_item title="Leakage"]

For the year 2017/18 average leakage is calculated (post Maximum Likelihood Estimate (MLE)) at 32.9 Ml/d. This is a failure against the target of 29.9 Ml/d. The graph below shows the long term trend in leakage performance.

<a href="https://www.portsmouthwater.co.uk/wp-content/uploads/2018/07/leaks.png"><img class="aligncenter wp-image-7166 size-full" src="https://www.portsmouthwater.co.uk/wp-content/uploads/2018/07/leaks.png" alt="" width="611" height="368" /></a>

Leakage was significantly impacted by weather events throughout the year resulting in a higher overall leakage compared to the previous year. Leakage began the year above target at 30.9 Ml/d as the company was still recovering from high winter leakage. We then experienced an increase in late April and early May due to ground movement associated with a reduction in soil moisture content. Leakage was reduced by the end of May.

Leakage rose again over the summer period and remained steady during the autumn despite efforts in leak detection and repair. We then experienced four separate Winter Events, compared to an average of two which are typically caused by an extended period of cold weather and/or a quick thaw. In particular the ‘Beast from the East’ had a significant impact. Leakage rose by 7.05 Ml/d after the thaw, with bursts roughly 3 times higher than the average for March.

[/accordion_item]

[accordion_item title="Burst Mains"]

The number of burst mains experienced in 2017/18 was 347, compared to 298 that occurred in 2016/17 and our annual target of 342.  It equates to 104 bursts per 1,000km in the reporting year.

Almost 20% of the bursts experienced in the year occurred in March 2018, when the Beast from the East resulted in rapid temperature changes. This measure is very dependent on weather conditions.

<a href="https://www.portsmouthwater.co.uk/wp-content/uploads/2018/07/burst.png"><img class="aligncenter wp-image-7167 size-full" src="https://www.portsmouthwater.co.uk/wp-content/uploads/2018/07/burst.png" alt="" width="628" height="313" /></a>

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<a href="https://www.portsmouthwater.co.uk/wp-content/uploads/2018/07/WRMP-Annual-Review-June-2018.pdf">To view a copy of the Annual Review for 2018, please click here</a>

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