The Weapon Beneath the Woodpile

This article is a tribute to the late Auckland historian Dick Scott, whose 1954 The Story of Parihaka became one of the most influential historical works published in this country. Scott’s other best-known works are left-wing exposés of historical events, such as Would a Good Man Die? Niue Island, New Zealand and the Late Mr Larsen (1993). Others are local histories, including Seven Lives on Salt River (1987), an account of the watery district of Pāhi on the Kaipara Harbour. The remainder are industry or company histories, and particularly histories of New Zealand’s wine industry.

REASONS FOR NON-COMPLIANCE WITH THE MAXIMUM PERMISSIBLE CONCENTRATIONS OF HAZARD CLASS 4E SUBSTANCES IN THE SMALL RIVER CONTROL POINT – DRAINAGE AND WASTE WATER RECEIVERS

Purpose: to determine the reasons of non-compliance with the maximum permissible concentration of the hazard class 4e substances for water bodies of fishery significance (MPCfs) in the small rivers control point – receivers of drainage and waste waters (DWW). Materials and methods. The research object is the Salt river Semikarakorsk district Rostov region, the catchment area of which is an anthropogenically transformed agricultural landscape. As background concentrations, the data from official certificates on background concentrations in the investigated water body in the section 500 m above the DWW outlet are used. Results. The processes of salt-forming ions dilution belonging to the hazard class 4e substances in the aquatic environment of the Salt river when DWW enter it at the release site to the control point according to the method of A. V. Frolov – I. D. Rodziller were modified. It has been found that important characteristics of dilution processes are the ratio of the flow rates of the river and in the reservoir, as well as the background (Cf) and maximum permissible concentration of the substance. So, for the calcium ion Cf = 105 mg/dm³, MPCfs = 180 mg/dm³, the concentration of the substance in the most polluted jet from the release site to the control point varies from 180 to 107.8 mg/dm³. For sulfate ion Cf = 385 mg/dm³, MPCfs = 100 mg/dm³, the concentration varies from 100 to 232.5 mg/dm³. Conclusions. It has been found that the reasons for non-compliance with the maximum permissible concentrations of the hazard class 4e substances in the control point of small rivers are a high background concentration of salt-forming ions belonging to the 4e hazard class, comparable flows of rivers and DWW. The reasons for the weak dilution are the shallow depth of the river, low flow velocity, as well as high initial mineralization of natural water. Therefore, it is necessary to amend the Russian legislation in terms of regional permissible concentrations in water bodies, taking into account the regional characteristics of the hydrochemical regime of water bodies, river runoff, and the hydrochemical composition of the upper horizons of groundwater.

Winter Inputs Buffer Streamflow Sensitivity to Snowpack Losses in the Salt River Watershed in the Lower Colorado River Basin

Recent streamflow declines in the Upper Colorado River Basin raise concerns about the sensitivity of water supply for 40 million people to rising temperatures. Yet, other studies in western US river basins present a paradox: streamflow has not consistently declined with warming and snow loss. A potential explanation for this lack of consistency is warming-induced production of winter runoff when potential evaporative losses are low. This mechanism is more likely in basins at lower elevations or latitudes with relatively warm winter temperatures and intermittent snowpacks. We test whether this accounts for streamflow patterns in nine gaged basins of the Salt River and its tributaries, which is a sub-basin in the Lower Colorado River Basin (LCRB). We develop a basin-scale model that separates snow and rainfall inputs and simulates snow accumulation and melt using temperature, precipitation, and relative humidity. Despite significant warming from 1968–2011 and snow loss in many of the basins, annual and seasonal streamflow did not decline. Between 25% and 50% of annual streamflow is generated in winter (NDJF) when runoff ratios are generally higher and potential evapotranspiration losses are one-third of potential losses in spring (MAMJ). Sub-annual streamflow responses to winter inputs were larger and more efficient than spring and summer responses and their frequencies and magnitudes increased in 1968–2011 compared to 1929–1967. In total, 75% of the largest winter events were associated with atmospheric rivers, which can produce large cool-season streamflow peaks. We conclude that temperature-induced snow loss in this LCRB sub-basin was moderated by enhanced winter hydrological inputs and streamflow production.